Fry the onion and garlic in olive oil for 15 minutes
in the meantime - take care of the tomatoes - in a big pot bring the water into a boil and add the tomatoes for 2-3 minutes. now transfer into ice water and easily remove the shell of the scalded tomatoes.
cut the tomatoes into cubes and add chili, sugar, salt and pepper. cook on a low flame for an hour. if needed add water, but try not to dilute too much
add the basil and puree using a hand blender.
serve with fresh croutons- cut bread into cubes, sprinkle olive oil, ground pepper and salt and bake for 10 minutes.
If you feel like changing the recipe a bit - you can try adding some Paprika, Thyme, oregano or Red wine.