This vegetable au gratin is the side dish I make on repeat all winter. Thin layers of potato, sweet potato and zucchini in a rich cream sauce, baked until golden and bubbling, with just 15 minutes of prep.
If you love a cheesy bake, my Cheesy Broccoli and Cauliflower Bake and Creamy Cheesy Vegetable Quinoa Bake get the same treatment.
A Quick Look At The Recipe
🥔 Recipe: Vegetable Au Gratin
⏰ Ready In: 1 hour 45 minutes (15 minutes prep, then the oven does the rest)
🍽️ Perfect For: a side dish, or a vegetarian main
🧀 Main Ingredients: potato, sweet potato, zucchini, cream, Gruyere or cheddar
🌱 Dietary Info: vegetarian, gluten-free, freezer-friendly, Thermomix or conventional method
💛 Why You'll Love It: just 5 ingredients, no béchamel to make, and it's the kind of cheesy vegetable bake that gets fussy eaters asking for seconds
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This is proper comfort food, rich, creamy and cheesy, and perfect for cold nights. Serve it as a side dish, or bulk it up as a main for an easy family dinner.
Like my Cheesy Mashed Potatoes, Macaroni & Vegetable Frittata Bake and Vegetable Fritters, it's also a great way to use up any vegetables sitting in the fridge.
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Why You're Going To Love This Recipe
- Easy - just 15 minutes to prepare, and there's no béchamel to make.
- Kid-friendly - baked vegetables with lots of melted cheese is always a winner with kids, and it's healthy too.
- Versatile - serve on its own as a light meal, or as a side to your favourite grilled meat or fish.
- Freezer-friendly - freeze for up to a month, thaw in the fridge overnight, then reheat for an easy weeknight dinner.
- Conventional or Thermomix - both methods are written in the recipe card at the end of the post.
Vegetable Au Gratin Ingredients
You only need 5 ingredients to make this vegetable gratin.
Note: Scroll to the recipe card at the bottom for the ingredients quantities and full detailed method.
- Cream - use a full-fat thickened cream (or heavy cream) for a rich, creamy sauce, or a 'light' version if you prefer.
- Vegetables - I use a combination of potato, sweet potato and zucchini, but you can use your favourites (see Variations below).
- Cheese - Gruyere or cheddar for the perfect bubbling, golden top.
Variations
- Vegetable swaps: as long as your total weight is around 1.5 kilograms, swap in broccoli, cauliflower, carrot, mushroom, green beans or parsnip alongside (or instead of) the potato, sweet potato and zucchini.
- Root vegetable version: use swede, turnip, beetroot or eggplant for a heartier, more rustic gratin.
- Extra crunch: sprinkle breadcrumbs over the top with the cheese and bake until golden and crunchy.
- Bulk it up: stir through cooked, shredded chicken or crispy bacon before baking to turn this side into a full main meal.
How To Make Vegetable Au Gratin
Nothing fancy needed, just a small jug or Thermomix, a sharp knife (or a mandoline if you have one, for thin, even slices) and a 2 litre / 8 cup capacity baking dish. I use a fan-forced oven, if you're using conventional, increase the temperature by 10-20 degrees Celsius.
Just 15 minutes to prepare, then let the oven do the rest of the work.
Note: Scroll to the recipe card at the bottom for the ingredients quantities and full detailed method.
- Step 1: Make the cream mixture. Preheat the oven and grease a baking dish. Whisk the cream, melted butter, garlic and salt and pepper together until well combined.
- Step 2: Prepare and arrange the vegetables. Peel the vegetables if needed and slice them very thinly. Arrange the slices in the prepared dish.
- Step 3: Pour and bake covered. Pour the cream mixture over the vegetables. Cover tightly with foil and bake until the vegetables are soft.
- Step 4: Add the cheese and finish baking. Remove the foil, sprinkle over the grated cheese, then return to the oven and bake until the cheese is golden and bubbling. For an extra-golden top, switch to the grill for the last 2-3 minutes, watching closely so it doesn't catch.
Team Thermomix? Mix the cream, melted butter, garlic and salt and pepper for 10 seconds, Speed 8, then continue with the vegetables and baking as above.
Allow the vegetable au gratin to stand for a few minutes before serving.
Recipe Tips
- Vegetables - use any vegetables you like, as long as the total weight equals approx 1.5 kilograms. Potato, sweet potato and zucchini is my go-to, but see Variations above for more ideas.
- Potato - use a starchy potato (such as Sebago here in Australia) rather than a waxy one, as the starch absorbs the liquid much better.
- Slice evenly - keep your slices around 3mm thick and as even as possible so everything cooks at the same rate.
- Golden, bubbling top - once the cheese has melted, pop it under the grill for the last 2-3 minutes for that deep golden, bubbling finish. Keep the oven door cracked open and watch it the whole time.
- Breadcrumbs - sprinkle over the top with the grated cheese and bake until crunchy, if you like extra texture.
- Storage - store leftovers in an airtight container in the fridge for up to three days.
Vegetable Au Gratin FAQs
Yes! Freeze it in an airtight container for up to 1 month (thaw in the fridge overnight before reheating). To reheat, place in the oven at a medium temperature until heated through, or reheat individual portions in the microwave.
Au gratin is a French term given to a dish that's topped with a browned crust, usually breadcrumbs or cheese.
If your sliced potatoes were soaked in water and not drained well, it can make your gratin watery, as can using a waxy potato rather than a starchy one, since the starch absorbs the liquid.
If it's still too watery once baked, it may just need a bit longer in the oven.
Yes. Assemble the dish up to the point of baking, cover tightly and refrigerate for up to 24 hours. Bake straight from the fridge as directed, allowing a few extra minutes since it's starting cold.
This recipe works best with fresh vegetables sliced very thinly, as frozen vegetables release extra water as they cook and can make the gratin soggy. If you do use frozen, thaw and pat them very dry first.
More Cheesy Vegetable Bake Recipes
If you loved this, here are a few more cheesy vegetable bakes worth trying next:
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Vegetable Au Gratin
Ingredients
- 1 ½ cups (360 ml) thickened cream heavy cream
- 30 g (2 tbs) butter melted
- 2 teaspoon minced garlic
- salt and pepper to taste
- 1.5 kg (approx) thinly sliced vegetables potato, sweet potato, zucchini (see notes)
- 2 ½ cups Gruyere or cheddar cheese grated
Instructions
- Preheat the oven to 180 degrees celsius (fan-forced). Grease a 2 litre / 8 cup capacity baking dish and set aside.
- Place the cream, melted butter, minced garlic and salt and pepper into a small bowl or jug. Whisk until combined. If using a Thermomix: Mix for 10 seconds, Speed 8.
- Peel the vegetables, and then chop into very thin slices (approx 3mm thick).
- Arrange the vegetables in the prepared dish.
- Pour over the cream mixture.
- Cover tightly with foil and bake for 1 hour and 15 minutes. Check that the vegetables are soft (if not, cover with foil and continue cooking until soft).
- Remove the foil and sprinkle over the grated cheese.
- Bake for 15 minutes or until the cheese is bubbling and golden.
- Allow the vegetable bake to stand for a few minutes before serving.
Notes
- Vegetables - you can use any vegetables you like - as long as the total weight equals approx 1.5 kilograms. I recommend using potato, sweet potato and zucchini. However, you could also add eggplant, swede, turnip, beetroot etc.
- Potato - use a starchy potato (such as Sebago here in Australia), rather than a waxy potato as the starch absorbs the liquid better.
- Breadcrumbs - if you like, you can sprinkle breadcrumbs over the top with the grated cheese and bake until crunchy.
- Storage - store any leftovers in an airtight container in the fridge for up to three days.
- Freeze in an airtight container for up to 1 month (allow to defrost in the fridge overnight before reheating). To reheat, place in the oven at a medium temperature until heated through. You can also reheat individual portions in the microwave.
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