Easy Canned Pizza Sauce Recipe With Frozen or Fresh Tomatoes

- (Assuming they were cleaned and cored before freezing) leave to thaw 24 hours; drain accumulated juices.

- Put the thawed tomatoes through a strainer to remove seeds and peels.

- Wash, core and halve tomatoes. Heat to boiling and then remove from heat (TIP: I use a 12-quart stockpot and a 6-quart soup pot for 22 pounds).

- Put through a strainer while warm to remove seeds and peels.

- In a 12-quart or larger stockpot cook onions and garlic in the olive oil over medium heat until the onion softens, 5-10 minutes. Add tomato puree and all the seasonings (basil through pepper flakes). Bring to a boil, reduce heat and cook for about 30 minutes, uncovered. Process with an immersion blender to make a smoother sauce (or carefully blend in batches).

- Bring back to a boil; reduce heat and simmer, uncovered, until sauce reaches desired consistency (reduced by 1/4 to 1/3), usually an hour or two, depending on if you started with fresh or frozen tomatoes (it may take longer - cook until desired consistency). Make sure to stir occasionally to prevent sticking (TIP: if you have a thin-bottomed stock-pot, stir more often to prevent scorching).

- Add the lemon juice or citric acid to each clean, warm jar, fill jar with sauce leaving 1/2-inch headspace and attach lids and rings until fingertip-tight. Place in canner rack and repeat with remaining jars to fill canner (keep sauce and jars warm, as you will need to do a couple canner loads when using half-pints-see how to water bath can here).

- Process both pints and half-pints for 35 minutes in a boiling-water canner.

- Remove to a towel-lined surface and let sit undisturbed for 24 hours before checking seals, labeling and storing in a cool, dark place.