Sauté the base: Heat olive oil in a large skillet over medium heat. Add the diced onion and sauté until softened. Add the chopped red bell pepper and cook until it begins to soften.
Cook the tomatoes: Stir in the chopped tomatoes and red pepper flakes. Simmer for about 15 minutes, allowing the flavors to develop. Season with salt, black pepper, oregano, and basil. Cook for another 1–2 minutes, then remove from heat.
Blend: Let the mixture cool slightly, then transfer to a blender or food processor. Blend until smooth, or pulse for a chunkier texture.
Combine: Transfer to a bowl and stir in the grated Pecorino Romano and ricotta until creamy and well combined.