Place a pot of water to boil.
Make a criss-cross on the tomato heads and drop them in water.
Let boil for 4-5 minutes, cover for 2-3 minutes.
Drain the water, let the tomatoes cool.
Peel off the skin and blend to make a smooth purée.
Add 1 tbsp of olive oil in a pan and add chopped onion and garlic, sauté for a minute or two.
Add the prepared purée.
Add the pizza seasoning, chilly flakes, salt.
Add the tomato ketchup and the ready purée.
Cook for 4-5 minutes or until completely cooked.