Best-of-the-best ratatouille

Method

1. Finely slice the courgettes, aubergines and tomatoes, taking care to keep them all the same thickness (5mm is ideal; a good mandoline makes this task much easier). Lay out on several kitchen paper-lined trays, then sprinkle generously with fine sea salt and leave for at least an hour. Pat dry with kitchen paper, trying to get rid of as much liquid as possible, then sprinkle with ground black pepper and the thyme leaves.
2. Meanwhile, make the sauce. Heat the oil in a saucepan over a medium heat. Add the onion, cook for 3 minutes until starting to soften, then add the garlic  and cook for another few minutes until everything is soft but not coloured. Pour in the tinned tomatoes, then half-fill the tin with water, swish it around and pour the water in too. Add the butter and a pinch of salt and pepper, then stir and bring to a gentle simmer. Turn the heat to low and cook for 25-30 minutes.
3. Taste and add more salt or pepper if it needs it, then use a stick blender to whizz the mixture to a smooth sauce. Pour into the oven dish, then stir in the herbes de provence and chopped roasted peppers.
4. Now you’re ready to assemble the ratatouille. Construct tall stacks of sliced veg, starting with a piece of aubergine, followed by yellow courgette, green courgette, tomato and a basil leaf (keep a few leaves back for the final garnish). Arrange on their sides in the oven dish, packing them in tightly so each slice of veg holds up the next, in a concentric pattern, starting from the outside and spiralling into or filling out the centre.
5. Set aside for 10-15 minutes while you heat the oven to 170°C fan/gas 5. Dab the top with kitchen paper to remove any residual water, then cover the dish with a sheet of baking paper and tightly seal with a sheet of foil. Bake for 40 minutes, then remove the foil and paper, brush the tops of the vegetables with a little more oil and return to the oven, uncovered, for 15-20 minutes more. The vegetables should just be starting to brown and crisp when it’s ready. Sprinkle with any remaining basil leaves.