Prepare the tomatoes. Halve the tomatoes, then use a spoon to deseed them. Discard the seeds. Place the tomatoes in a food processor and blend them until they are smooth. Place the tomatoes in a strainer and allow the excess liquid to strain for about 5 minutes.
Sautè the ingredients. Place a medium sized pot over medium heat. Once the pot is hot, add the olive oil. Add the onion and garlic to the pot and sautè for 2 minutes. Add the tomatoes and bring it to a light boil. Reduce the heat to a simmer and add the basil and salt.
Simmer the sauce. Allow the sauce to simmer for 40 minutes. Stir the sauce frequently.
Serve. Remove the basil from the sauce and discard. Serve this sauce with your favorite pasta. Mangia!