Grease a large round baking 30cm baking dish with butter and set aside.
Place the peeled and sliced apples into a medium saucepan with the water, caster sugar, lemon juice, cinnamon and nutmeg.
Bring to a low simmer for 5-10 minutes or until just softened. Drain off the excess liquid. Place the stewed apples into the baking dish.
To make the crumble, place the oats, brown sugar, plain flour and butter into a bowl. Use your fingers to squeeze and break up the lumps of butter until crumbs have formed and all of the oats and flour are completely combined with the butter.
Sprinkle the crumble over the apple and place into the preheated oven.
Cook for 35-40 minutes or until the crumble is golden and crunchy.
Serve immediately with ice-cream, cream or custard.
Thermomix Instructions - Click the link in the notes section below for the Thermomix recipe.
Variety of apples - You can use any type of apple you like for this recipe! Granny Smith's are generally considered the best apples to use for apple crumble. They don’t go as mushy as some other varieties and their tartness is the perfect contrast to the sweet brown sugar and oat crumble. Alternatively, you can use any variety of apple you like, such as Pink Lady, Jonathan, Red Delicious, Jonagold, Honeycrisp, Braeburn, Cripps Pink etc.
Gluten-free alternative - rolled oats are already gluten-free so all you need to do is substitute the plain flour for gluten-free plain flour to make this a gluten-free apple crumble.
Make ahead of time - Apple Crumble can be prepared and cooked ahead of time. Simply reheat when ready to serve.
Storing - store in the fridge for up to 3 days.
Freeze - freeze any leftovers for up to 3 months.
Reheating - place leftovers directly from the fridge into a warm oven, or alternatively microwave to reheat. Frozen leftover apple crumble can be defrosted and reheated in the microwave or a low temperature oven as well.