Slowly saute 4 cloves of garlic in a generous amount of olive oil so it becomes sweet and not brown.
Then add large can of peeled, crushed tomatoes (if you can get San Marzano brand imported from Sicily, that is best) and a can of tomato paste.
Stir it all together until it is bubbling then turn the heat to low and simmer, stirring occasionally, for at least two hours. The slow low heat makes the tomatoes sweet. Add nothing else but some salt after you add the tomatoes. If you cook it long and slowly, it develops all the flavor you need.
This could take two hours.