Place the peeled pumpkin on a baking sheet and cut into small pieces, the quartered tomato, the sliced seedless chili pepper, the garlic cloves, a drizzle of olive oil, oregano and pepper. Cook for 30 minutes at 180°C.
During this time, put the leek in a saucepan and the peeled zucchini cut into slices. Add the baked vegetable mixture and cover two thirds of the pot with boiling water. Season with salt, cover and cook over low heat for 20 minutes.
Reduce the vegetables to a creamy purée and serve with a drizzle of olive oil.