Wash tomatoes, cut them into half, and cut out any brown stems.
Place them cut sides of the tomatoes down on a cookie sheet and bake at 350°F (117°C) for about 30 minutes until the skin wrinkles and juice starts to come out.
Put the roasted tomatoes, garlic, olive oil, pesto or basil, salt, and sugar into a blender.
Blend until creamy (Add a tiny bit of water if needed).
Serve as you would any tomato sauce.
Notes
If the tomatoes are in season, you will not need any added sugar.
If you are using less ripe tomatoes, you may want a little sugar to sweeten up the sauce.
If your tomatoes dry out too much at a tablespoon or 2 of water while blending.