3 pounds ripe Roma tomatoes, halved lengthwise
1/4 cup olive oil
1 tablespoon sea salt
1 1/2 teaspoons freshly ground black pepper
4 tablespoons butter
2 medium onions, chopped
6 garlic cloves, minced
1/4 teaspoon crushed red pepper flakes
1 (28-ounce) can San Marzano (Italian plum) tomatoes, with juice
2 cups chopped fresh basil leaves, packed plus sprigs of fresh basil for garnish
2 teaspoons fresh thyme leaves
1 teaspoon fresh sage leaves, chopped
3 cups vegetable stock – MSG-free if possible
Preheat the oven to 400 degrees. Toss together the Roma tomatoes, 1/4 cup olive oil, salt, and pepper. Spread the tomatoes in 1 layer on a rimmed baking sheet and roast for 45 minutes.
In a large soup pot, melt butter, then add onions, garlic and red pepper flakes. Saute gently until onions are translucent. Add the can of tomatoes, basil, thyme, and vegetable stock. Add the oven-roasted tomatoes, including any liquid on the baking sheet. Bring to a boil and simmer uncovered for 40 minutes. Briefly use an immersion blender if desired. Serve and garnish with fresh basil sprigs.