Sauté chopped onion in tomato oil for 5 minutes. Add garlic and sauté for 2–3 more minutes.
Add 1 cup broth to a blender with onion, garlic, and remaining ingredients (except pasta, basil, and red pepper flakes). Blend until smooth, adding broth as needed for consistency.
Season with salt and pepper to taste.
Simmer sauce to thicken.
Add in pasta and stir to coat.
Garnish with basil and red pepper flakes. Optional: Pairs well with sausage.