Heat 3 tablespoons olive oil in a large pot over medium-high heat. Add ground beef and cook, stirring occasionally, until it brown, about 5 minutes.Drain fat and add onions and garlic and continue cooking until the onions become translucent. Stir in the tomato puree; rinse each can with 1/2 cup water and add to the pot. Stir in the basil, oregano and 1 1/2 tablespoon of salt. Bring to a simmer, cover and let cook for 2 1/2 hours. Remove the basil, and salt and pepper to taste.