The peppers can be pre-roasted in the oven, then peeled and used. Otherwise you can proceed without doing this, cutting all the ingredients and browning onions and garlic with a little olive oil, then add the peppers, carrots, celery and chilli powder. Stir fry for a few minutes then add the canned tomatoes. When the vegetables have softened, add some vegetable broth or water, only if needed. Blend everything with a hand blender and keep cooking until you have achieved the desired consistency. Garnish with fresh basil and some ground almonds (or use grated cheese).