Rinse the tomatoes. Remove the core of the tomato. Cut the tomatoes in half lengthwise. Cut the red onion into large pieces. Place the tomatoes and red onions in a large bowl. Add the whole garlic cloves, olive oil, salt, pepper, Italian seasoning and sugar. Toss to coat all of the ingredients with the olive oil. Place the ingredients on a cookie sheet with the tomatoes face down. Place them in an oven that has been preheated to 450 degrees. Bake the tomatoes until they are golden brown and slightly charred on top (not black, but dark brown is okay). Once the tomatoes are soft and tender, and the onions and garlic are cooked, remove the tomatoes from the oven. Let them cool for a few minutes and then pour the entire pan of ingredients into a blender (be careful, they will be hot). If you are using a smaller blender, just blend half at a time. Blend the mixture carefully with the lid securely fit to the jar. Blend until the sauce is completely smooth. Season sauce with more salt, sugar or pepper as needed. Serve the sauce over noodles with parmesan cheese. Meatballs make a nice addition too.
Notes
*HEALTHIER OPTION: Serve over whole grain pasta. If serving with meatballs, serve with turkey meatballs.