Preheat the oven to 180 °C (160 °C fan). Finely chop the onion and garlic and cook both gently in olive oil until soft and translucent.
Add the passata, herbes de Provence, salt and pepper and let the sauce reduce for a few minutes. Then spread it in the baking dish.
Cut the courgette, aubergine, tomatoes and pepper into thin, even slices. That way the veg cooks evenly later.
Layer the vegetable slices alternately and slightly overlapping in the dish. Drizzle everything with olive oil and season with thyme, salt and pepper.
Cover the dish and bake at 180 °C for 30 minutes, until the veg softens. Then remove the cover and bake for another 10–15 minutes, until the top is lightly browned.
Serve the ratatouille bake hot, ideally straight from the dish. A green salad or gluten-free bread goes well with it.
Good to know
A bake like this doesn't make a fuss and still tastes of a lot. Warm, juicy, uncomplicated – just right when veg should take centre stage.
Swaps
Pepper → fennel (also provides fibre and a different, slightly sweet flavour); aubergine → more courgette (a little milder and more watery); passata → unsweetened chopped tomatoes (similar nutrition, a little more texture); olive oil → avocado oil (heat-stable, with monounsaturated fatty acids)
Allergens
The dish is gluten-free and free from milk, egg and nuts. Usually well suited to children if the garlic and pepper are used sparingly. During pregnancy it's fine with thoroughly cooked veg.