Step 1

Core and roughly chop the tomatoes.

Step 2

In a large pot heat the olive oil over medium heat and sauté the onion, garlic, and salt until transparent, about 10 minutes. Add the chopped tomatoes. Bring to a boil and simmer for 20 to 30 minutes, until the tomatoes have broken down.

Step 3

Position a food mill or sieve over a large bowl and begin to press the hot tomatoes, onions and garlic through it, stopping to clear out the skins and seeds as needed (discard or compost the skins and seeds). Alternatively, you can run the vegetables through the food processor but this won't remove the skins and seeds.

Step 4

Return the pressed tomatoes to the pot and simmer the sauce until it is reduced by one-third to one-half. The time for this will vary based on how juicy your tomatoes are - it took 4 hours for our sauce to cook down properly because our tomatoes were very juicy. About half an hour before you're ready to can, stir in the basil and parsley.

Step 5

At the same time that you add the herbs, prepare a water bath and submerge 4 quart jars in the water and boil for 10 minutes. Place lids in a small saucepan over very low heat to gently simmer while you prepare the tomatoes.

Step 6

Take your prepared jars from the boiling water (of course, dumping the water back into the canning pot before proceeding) and add 3 tablespoons of bottled lemon juice to the bottom of each jar. Using a large ladle, transfer the hot tomato sauce into the jars, leaving 1/2 inch headspace between the top of the sauce and the rim of the jar.

Step 7

Wipe the rims with a clean kitchen towel, add lids and rings, and process in a boiling water bath for 40 minutes. For smaller jars, reduce the processing time by 5 minutes.

Step 8

Transfer the processed jars to a clean towel and allow the jars to sit untouched at room temperature for 24 hours before checking the lids for a seal and storing for up to 1 year. If any lids have not sealed, as evidenced by that characteristic "pop", put the unsealed jars in the refrigerator immediately and use the sauce within 1 week.