Preheat oven: Preheat the oven to 400°F. Grab a large casserole dish and set aside.

Prep the garlic: Remove loose skin from 1 head of garlic. Cut about 1/4 inch off the top to expose the cloves. Wrap tightly in parchment paper (optional) and foil, sealing with no holes. Set aside.

Combine and roast: In the casserole dish, combine 2 pounds medium tomatoes, stems removed, 1 large onion, peeled and roughly chopped, 0.3 cups extra-virgin olive oil, 2 teaspoons Italian seasoning, 0.5 teaspoons kosher salt, 0.5 teaspoons sugar, 0.3 teaspoons black pepper, and 0.3 teaspoons crushed red pepper flakes. Mix well. Place the wrapped garlic in a corner of the dish and roast for about 40 minutes

, or until tomato skins start to lift.

Let it cool: Remove from the oven and let cool for 15 minutes

Remove roasted garlic: Open the roasted garlic (keeping it in the parchment and foil) and gently squeeze the cloves into a food processor using oven mitts or a towel. Avoid letting skins fall in.

Transfer to food processor: Transfer the roasted tomatoes, onion, and all juices from the baking dish into the food processor.

Add tomato paste and blend: Add 3 tablespoons tomato paste and pulse until you reach your desired consistency, smooth or with some texture.

Fold in basil: Add 0.3 cups fresh thinly sliced basil leaves, plus more for garnish and pulse just until combined, not fully blended. Adjust seasonings to taste.