Take your tomatoes and steam them for 10-15 minutes. This is to release the skin from the tomatoes. Peel the tomatoes and set aside.
Heat up the oil and saute the onion for about 5-6 minutes on medium heat. Add the Basil, Garlic, and Spices and add the tomatoes one by one smashing them with a potato masher or your hands, whichever you prefer.
Let the pot simmer for as long as you can let it simmer. Normally, this is about an hour so that all the flavors can marry.