Start by washing the heirloom tomatoes thoroughly, then chop them into chunky pieces, keeping the skins on to add color and texture to the sauce.
Heat the olive oil in a large saucepan over medium heat until it shimmers and begins to smell fragrant.
Add the minced garlic to the hot oil and sauté for about 30 seconds, until it becomes fragrant and slightly golden, releasing a rich aroma.
Pour the chopped tomatoes into the pan, stirring gently to coat them in the oil and garlic, then increase the heat slightly to bring the mixture to a gentle simmer.
Sprinkle in the sea salt and red pepper flakes, then stir to incorporate all the seasonings. Let the sauce simmer uncovered for about 20-30 minutes, stirring occasionally, until it thickens and the tomatoes break down into a chunky, rustic mixture.
As the sauce thickens, taste and adjust the salt if needed. Once the sauce reaches your desired consistency, remove it from the heat and stir in the chopped fresh basil for a burst of herbal freshness.
Serve the sauce hot over your favorite pasta, garnished with extra basil if desired. Enjoy the vibrant, chunky texture and complex flavors of this imperfect, beautifully rustic tomato sauce.