Preheat the oven to 190 C, 170 Fan, Gas 5. Arrange all the vegetables in a large ovenproof dish, layering them evenly and distributing the garlic, dill stalks and plenty of salt and pepper as you do.
Add 150ml water and top with the olive oil. Cover with foil and bake in the oven for 45 minutes, then remove the foil and increase the heat to 210 C, 190 Fan gas 6-7.
Cook until all the vegetables are completely tender and the top layer is beginning to crisp and colour in places.
Remove from the oven and set aside for at least 15 minutes before adding the chopped dill leaves and the chilli flakes and serving withthe sour cream.