Big-Batch Freezer Tomato Sauce

From the garden

• 8 lb ripe tomatoes, cored and roughly chopped
• 2 medium yellow onions, diced
• 6 cloves garlic, sliced
• ½ cup fresh basil, leaves torn (optional)

From the pantry

• ¼ cup olive oil
• salt — to taste

1. Warm the olive oil in your biggest heavy pot over medium heat. Cook the onions with a pinch of salt until soft and translucent, about 6 minutes, then add the garlic and cook 1 minute more, until fragrant.
2. Add the chopped tomatoes with all their juices and a good pinch of salt. Bring to a lively simmer and cook uncovered, stirring occasionally and crushing the tomatoes against the pot, 45–60 minutes, until thick enough that a spoon leaves a trail. No need to peel — the skins soften and disappear into the sauce (blitz briefly with an immersion blender if you want it perfectly smooth).
3. Stir in the basil, if using, and season with salt until the sauce tastes bright and full. Take the pot off the heat.
4. Cool the sauce quickly — set the pot in a sink of cold water and stir until barely warm. Never bag it hot; a warm bag in the freezer thaws its neighbors.
5. Ladle into quart freezer bags in 3–4 cup portions, press out the air, seal, and freeze flat on a sheet pan. Once solid, the slabs stack like books. Label and date every bag.