Peel and chop onions and garlic. Drain the tomatoes, catching the juice. Roughly chop the tomatoes and remove rests of skin.
Heat up a large pot and add the olive oil. Then put in the onions and saute until they glisten. Add the garlic and roast it with the onions another 3 minutes.
Put in the tomato paste and stir. Add the sugar and mix. Then add the tomatoes, the juice and everything else. Bring to boil and then lower the heat.
Let the sauce simmer for about an hour until it becomes thick. Take out the bay leaf and season to taste.