Peel onion and garlic. Chop the onion finely, cut the garlic into thin slices. Heat oil in a pot. Fry onion and garlic in it. Deglaze with tomatoes and stock, bring to the boil and let it boil down at low heat for about 20 minutes.
Season soup with salt, cayenne pepper, sugar and pizza spice. Refine pizza soup with further ingredients as desired (see above).