• Prepare the tomatoes – Rinse and core the tomatoes. Cut them in half (or quarters if large). Place into a 9x13-inch baking dish.
• Add aromatics – Quarter the onion, chop carrots, and add whole garlic cloves (in skins with the top lightly cut off so the cloves are exposed) to the dish with the tomatoes.
• Season and coat – Drizzle olive oil over the vegetables. Sprinkle with salt, pepper, oregano, and red pepper flakes. Toss lightly to coat.
• Roast covered – Cover the baking dish with foil and roast at 400°F for 45 minutes.
• Roast uncovered – Remove the foil and roast another 45 minutes, until the tomatoes and vegetables are caramelized and tender.
• Cool slightly – Allow the roasted mixture to cool to room temperature or just lukewarm before blending.
• Blend smooth – Add the tomato mixture to the blender or food processor, making sure to squeeze the roasted garlic out of the skins. Add in the fresh basil. Blend everything until completely smooth.
• Optional mill step – For a silky sauce, pass through a food mill to remove seeds and skins.
• Simmer (optional but recommended) – Transfer sauce to a pot and simmer 20–30 minutes to thicken if desired.
• Serve – Toss immediately with hot pasta, use as a pizza base, or spoon over grilled chicken or vegetables.

Storing Options

• Freeze: Let sauce cool fully, then portion into freezer-safe containers or bags. Freeze up to 4 months. Thaw overnight in the fridge before reheating.
• Can: Sterilize jars, then ladle hot sauce into jars leaving ½-inch headspace. Add bottled lemon juice or citric acid to each jar. Wipe rims, secure lids, and process in a boiling water bath:

  Pints – 35 minutes

  Quarts – 40–45 minutes(Adjust for altitude: +5 minutes 1,001–3,000 ft, +10 minutes 3,001–6,000 ft, +15 minutes above 6,001 ft.)