The Best Fresh Tomato Sauce Recipe

Name: The Best Fresh Tomato Sauce Recipe
Ingredients: 10 pounds (4.5kg) ripe plum tomatoes, preferably mixed varieties (such as Romas, Amish Pastes, and San Marzanos), cut into large chunks, plus 15 pounds (6.8kg) ripe mixed tomatoes, mostly plums with a small portion of other tomatoes (such as beefsteaks), cut into large chunks; 3 tablespoons (45ml) extra-virgin olive oil, plus more for greasing; 1 large yellow onion, minced (see note); 3 medium cloves garlic, minced (see note); 2 large sprigs fresh basil; 1 small tomato plant cutting with about 5 leaves (optional); Kosher salt