|Preheat oven to 400 degrees F. Line a baking sheet with parchment paper.|
Halve the tomatoes and place on the prepared baking sheet. Drizzle with 1 tablespoon olive oil and season with salt and pepper. Bake for 45 minutes.
In a large saucepan, heat remaining olive oil and butter. Sauté onion, garlic and red pepper flakes until onions start to brown, approximately 20 minutes.
Stir remaining ingredients including roasted tomatoes and juice in pan. Simmer for 30 minutes, stirring frequently.
Pour into food processor and puree until smooth. Pour back into pan until ready to serve.