Sweet and delicious Blueberry Crumble Bars with a creamy lemon filling. Perfect for morning tea or a late night dessert treat, these crumble bars take just 20 minutes to prepare and taste amazing served either warm or cool.
Don't be fooled... they may look fancy, but they're SO simple to make.
These Lemon & Blueberry Crumble Bars are the answer when you have to choose between baking a dessert or a slice... and the choice is impossible!?
This recpe ticks ALL the boxes as both a decadent dessert and a tasty morning tea slice.
Just like my classic apple crumble slice, white chocolate and raspberry cheesecake slice and my famous brownies, these blueberry crumble bars are the perfect option at anytime of the day (or night!).
You can serve them cool on their own, or warmed up and drizzled with your favourite custard, cream or ice-cream as a simply scrumptious dessert!
Why You're Going To Love This Recipe
Once you try lemon blueberry crumble bars, you're going to have a new family favourite recipe... I promise!
- PACKED full of flavour - this slice has allllll the flavour you could possibly dream of! Sweet, crunchy streusel topping and base, combined with bursts of blueberries and a HEAVENLY creamy lemon filling.
- Fresh, zesty, light and creamy - I like to use a combination of lemon zest, lemon juice and lemon extract to really bump up the lemon flavour! But you can omit the lemon extract if you like (or if you don't have any at home). The lemon zest and lemon extract give the slice the strongest lemon flavour, while the lemon juice thickens the sweetened condensed milk filling.
- Looks fancy but is SO easy to make - while this layered slice may look impressive, it's actually incredibly easy to make! The crumble base and topping is made using the same mixture and the lemon filling is made using just one bowl and a whisk. SO simple!
- Can be served warm or cold - don't get me wrong, this is delicious served cold... but my favourite option is to heat it up a little and add a scoop of ice-cream or a drizzle of cream as a simply indulgent dessert.
- Freezer-friendly - pop any leftovers in the freezer for up to 3 months.
- Thermomix and conventional methods - these blueberry and lemon crumble bars can be made conventionally using a spoon and bowl, or in a Thermomix. I've included both methods in the recipe card at the bottom of the post.
What You Need
Lemon and Blueberry Crumble Bars are made using a handful of basic ingredients - many of which you will already have at home!
Note: please scroll to the recipe card at the bottom of the post for ingredient quantities and the full detailed method.
For The Crumble
- Plain flour - also known as all-purpose flour.
- Rolled oats - also known as old fashioned oats. It's best to use rolled oats rather than quick oats as they give the crumble a much nicer texture and crunch!
- Salt - a pinch of salt in the crumble perfectly balances the sweetness and creaminess of the lemon filling.
- Bi-carbonate soda - also known as baking soda.
- Raw sugar - this crystallised sugar gives the crumble it's epic CRUNCH!
- Brown sugar - while the raw sugar gives the crunch, the brown sugar adds a tasty chewiness and caramel flavour to the crumble.
- Butter - you can use either salted or unsalted butter. If using salted butter, omit the extra pinch of salt.
- Vanilla extract - you can use either vanilla extract or vanilla essence for this recipe.
For The Filling
- Sweetened condensed milk - use full fat (not skim) sweetened condensed milk as it sets firmer.
- Lemon zest - this gives the filling it's lemony flavour - add extra lemon zest if you're a real lemon lover.
- Lemon juice - the lemon juice reacts with the dairy in the sweetened condensed milk, causing it to thicken the mixture.
- Egg yolks - have your egg yolks at room temperature.
- Lemon extract - this is optional but really does give the filling an extra lemony kick! Personally, I love it, but you might find that the lemon zest and lemon juice are enough all on their own for you.
- Blueberries - you can use either fresh or frozen blueberries in this recipe.
Equipment Required
You may think this decadent slice looks a little tricky, but it's actually incredibly easy to make! ... and no fancy equipment required.
- Microwave, Thermomix or stove top - to melt the butter.
- Oven - I specify fan-forced oven temperatures in my recipes, so if you have a conventional oven, increase the temperature by between 10 and 20 degrees Celsius.
Step By Step Instructions
The crumble mixture is the same mix as the base, and the blueberries and creamy lemon filling are layered between the base and crumble - so....simple....
Note: please scroll to the recipe card at the bottom of the post for ingredient quantities and the full detailed method.
Step 1 - Prepare The Crumble
Place the plain flour, rolled oats, salt, bi-carbonate of soda, raw sugar and brown sugar into a large bowl and mix together to combine.
Pour over the melted butter and vanilla extract.
Stir until all of the dry ingredients have been coated in the butter and the mixture is crumbly.
Press just over half of the crumble mixture into the base of a lined slice tin (I use an 18cm x 28cm rectangular tin).
Bake for 15 minutes until lightly golden.
Step 2 - Add The Blueberries
Sprinkle the fresh or frozen blueberries over the cooked base.
Step 3 - Make The Lemon Filling
Place the sweetened condensed milk, lemon zest, lemon juice, egg yolks and lemon extract (if using) into a large bowl.
Whisk together until smooth and the filling has thickened slightly.
Pour the lemon filling over the blueberries and smooth out with the back of a spoon.
Step 4 - Sprinkle Over The Remaining Crumble
Use your fingers to sprinkle the remaining crumble over the filling.
Note: it's fine if there's some small sections of filling not covered in crumble.
Bake for 23-26 minutes or until golden and crunchy on top.
Serving Suggestions
The wonderful thing about this lemon and blueberry crumble slice (apart from the fact that it's absolutely delicious) is that it can be served warm or cool.
If serving warm, try serving with:
- a scoop of vanilla ice-cream
- homemade vanilla custard
- a drizzle of berry coulis
- a spoonful of thickened or whipped cream.
The perfect option for morning tea, afternoon tea or dessert!
FAQs
Making blueberry crumble bars with a creamy lemon filling is SO easy!
Here's some of my readers most common questions answered...
No. The lemon juice reacts with the dairy in the sweetened condensed milk which is what causes the filling to thicken. As coconut condensed milk contains no dairy, it will not thicken.
Yes, absolutely! Frozen blueberries tend to be more juicy when baked, but both are quite delicious.
As this recipe uses lemon juice and lemon zest, you can omit the lemon extract if you prefer. However, it does give the slice an extra lemony boost!
Expert Tips
Follow my tips for baking the perfect lemon and blueberry crumble slice every time!
- All ovens are different - the slice is ready when the crumble is golden. I specify degrees celsius (fan-forced) for my recipes. If you're using a conventional oven, increase the temperature by 10-20 degrees celsius.
- If you find that your crumble is over-browning, simply add a sheet of foil loosely over the top and continue baking.
- You can substitute the blueberries for strawberries, raspberries or blackberries if you prefer (or a combination of different berries!)
- This crumble slice is delicious served cool or warmed up with a scoop of ice-cream, custard, cream and/or berry coulis.
- Cut the slice using a sharp serrated knife.
- Store the slice in an airtight container in the fridge for up to one week.
- Freeze the slice in an airtight container for up to 3 months. Allow to defrost in the fridge before consuming.
More Blueberry Inspired Recipes
Blueberries are perfect for baking - with their sweet little bursts of flavour, they make the perfect addition to any slice or dessert.
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Lemon & Blueberry Crumble Bars
Ingredients
- 155 g (1¼ cups) plain flour
- 110 g (1¼ cups) rolled oats
- ½ tsp salt
- ½ tsp bi-carbonate of soda
- 100 g (½ cup) raw sugar
- 80 g (½ cup) brown sugar packed
- 170 g (¾ cup) butter melted
- 1 tsp vanilla extract
- 200 g (1 cup) frozen blueberries or fresh
- 395 g (1 tin) sweetened condensed milk
- 1 tbsp lemon zest finely grated, approximately 1 lemon
- 85 g (⅓ cup) lemon juice
- 2 large egg yolks
- ½ tsp lemon extract optional
Instructions
Conventional Method
- Preheat oven to 160 degrees celsius (fan-forced.
- Grease and line a 18cm x 28cm slice tray with baking paper, allowing the edges to overhang.
- In a large bowl, whisk together the plain flour, rolled oats, salt and bi-carbonate of soda.
- Stir in the raw sugar and brown sugar and mix until smooth.
- Stir vanilla extract into melted butter and pour mixture over dry ingredients.
- Stir mixture until well combined.
- Press just over half of the crumble mixture into the base of the prepared tin and use the back of a spoon to smooth the mixture into an even layer. Bake in the preheated oven for 15 minutes, until golden.
- Remove from oven and put aside (leave the oven turned on).
- Sprinkle the blueberries over the cooked crumble base.
- In a bowl, whisk together sweetened condensed milk, lemon zest, lemon juice, egg yolks and lemon extract (optional) until smooth and slightly thickened.
- Pour the lemon mixture over the blueberries and spread into an even layer.
- Sprinkle the remaining crumble mixture over the top of the lemon filling and blueberries.
- Bake in oven for 23 - 26 minutes or until lightly golden.
- Remove from oven and allow to cool.
- Cover and refrigerate for at least 2 hours (preferably overnight) then take it out and cut into squares. Store in airtight container in the refrigerator for up to 1 week.
Thermomix Method
- Preheat oven to 160 degrees celsius (fan-forced).Grease and line an 18cm x 28cm slice tray with baking paper, allowing the edges to overhang.
- Melt the butter and vanilla extract in the Thermomix bowl for 3 minutes, Speed 2, 80 degrees.
- Add the plain flour, rolled oats, salt, bi-carbonate of soda, brown sugar and raw sugar. Mix for 20 seconds on Reverse, Speed 2. Scrape down the sides. Mix for a further 20 seconds on Reverse, Speed 2.
- Press just over half of the crumble mixture into the base of the prepared tin and use the back of a spoon to smooth the mixture into an even layer. Bake in the preheated oven for 15 minutes, until golden.
- Remove from oven and put aside (leave the oven turned on.
- Place the zest of 1 lemon into the Thermomix bowl. Grate for 20 seconds, Speed 6. Scrape the sides of the bowl. Repeat until you have a very finely grated zest.
- Add the sweetened condensed milk, lemon juice, egg yolks and lemon extract (optional) and mix for 30 seconds, Speed 4. Scrape the sides of the bowl and mix for a further 30 seconds, Speed 4.
- Sprinkle the blueberries over the cooked crumble base. Pour lemon mixture over the blueberries and spread into an even layer.
- Sprinkle the remaining crumble mixture over the top of the lemon and blueberries.
- Bake in oven for 23 - 26 minutes or until lightly golden. Remove from oven and allow to cool.
- Cover and refrigerate for at least 2 hours (preferably overnight) then take it out and cut into squares. Store in airtight container in the refrigerator for up to 1 week.
Notes
- All ovens are different - the slice is ready when the crumble is golden. I specify degrees celsius (fan-forced) for my recipes. If you're using a conventional oven, increase the temperature by 10-20 degrees celsius.
- If you find that your crumble is over-browning, simply add a sheet of foil loosely over the top and continue baking.
- The lemon extract gives the slice an extra lemony flavour, but you can omit it if you prefer.
- You can substitute the blueberries for strawberries, raspberries or blackberries if you prefer (or a combination of different berries!)
- This crumble slice is delicious served cool or warmed up with a scoop of ice-cream, custard, cream and/or berry coulis.
- Cut the slice using a sharp serrated knife.
- Store the slice in an airtight container in the fridge for up to one week.
- Freeze the slice in an airtight container for up to 3 months. Allow to defrost in the fridge before consuming.
Lynne
Delicious slice, easy to make
great to make while blueberries are in good supply
Family loved it
Lucy
Fantastic!
Heather
Yum. So delicious. Easy to make and great to share.
Lucy
Thank you xx
Deb
So yum ! Especially good warm.I used mixed berries .This a keeper !
Lucy
Fantastic!!
Josie
This is my new favourite slice! It is a little bit dangerous as I tend to overindulge on it!
I use fresh blueberries and add some ground cinnamon to the crumble mixture. Delicious! Thank you!
Lucy
Fantastic!!!
Helen
Delicious slice, used home grown lemons, my girls free range eggs and Australian Blueberries... what more could you ask for!
Thanks for a lovely recipe.
Lucy
Fantastic!!!