Heat oil in a saucepan over medium heat; add onion and garlic, and cook, stirring, until soft, about 6 minutes. Add tomato paste, and cook, stirring, until lightly caramelized, about 2 minutes. Add tomatoes, chile, and bay leaf, and cook, stirring often, until sauce is reduced and thickened, about 5 minutes.

Remove and discard bay leaf, and season with salt and pepper. Puree sauce in a food processor or blender, and let cool to room temperature. Store in a container in the refrigerator for up to 2 weeks