For the polenta pizza, bring the vegetable soup to a boil with milk. Sprinkle in the cornmeal. Allow to swell over very moderate heat, stirring throughout, for 10-15 minutes, season with salt and pepper. Pour into a gratin dish (2 l capacity) and smooth. Boil tomatoes with crushed garlic clove in saucepan until thick, season with salt & pepper.
Spread cornmeal with the sugo, top with chopped anchovies, black olives (in small pieces), halved cherry tomatoes and drained capers, sprinkle with mozzarella (cut into cubes). Brush with a little olive oil. Bake in the preheated oven at 220° Celsius (gas 3-4, convection oven 20 minutes at 200° Celsius ) on the 2nd rack from the bottom for 15-20 minutes.
Cut the polenta pizza into pieces and serve warm.