Heat oven to 425°F.

Divide tomatoes, onions, and garlic between two rimmed sheet pans in a single layer. Place halved tomatoes cut-side up.

Drizzle with olive oil; sprinkle with Italian seasoning, salt, and pepper. Add optional tomato paste, anchovies, or carrot now.

Toss gently to coat, then spread back into an even layer.

Roast 35–45 minutes, until tomato edges brown, skins wrinkle and lift, and onion edges char slightly. Rotate pans halfway if using one oven. Cherry/grape tomatoes: 20–25 minutes.

Cool 10 minutes. Remove skins if desired.

Scrape everything — including all pan juices — into a blender. Add fresh basil now if using. Blend smooth, or pulse for a chunkier sauce.

Season to taste while warm: salt first, then sugar or honey if acidic, then vinegar or lemon if flat.

Serve over hot pasta with a splash of pasta water, or cool completely and freeze.

Quarter the recipe: 1 1/2 lbs roma tomatoes (halved), 1 small onion, 6–8 garlic cloves, 1 1/2 tbsp olive oil, 3/4 tsp Italian seasoning, 1/2 tsp salt. Toss, then spread in a single layer directly in the air fryer basket, cut-side up — no pan or liner. Cook at 400°F: 15–18 min for halved romas, 12–15 min for whole cherry/grape, 18–22 min for halved slicers. Shake halfway. Cool 5 minutes, tip everything into a bowl, blend, and season to taste.