1. Wash 30 pounds of tomatoes. Remove cores and quarter tomatoes. Boil 20 minutes, uncovered, in large pan (or pans).
2. Put through food strainer or food mill. Cook down tomatoes to reduce volume and make a thicker sauce. Reduce volume by 1/2 to 2/3rds.
3. While the sauce is cooking, finish the remaining prep work, like chopping your veggies and getting the lids and jars ready. Prepare pressure canner according to manufacturer’s instructions.

To Finish the Sauce

1. Saute in 1/4 cup butter or olive oil until tender: onions, garlic, celery or green pepper, and mushrooms.
2. Combine sauteed vegetables and tomatoes.
3. Add salt, black pepper, oregano, parsley and sugar.
4. Bring to a boil. Stir frequently to avoid burning. Reduce heat to simmer, keep hot while waiting to process.
5. Fill jars, leaving 1 inch headspace. Adjust lids.
6. Process in a pressure canner 20 minutes for pints, 25 minutes for quarts. If using a weighted-gauge canner, set at 10 pounds pressure at 0-1,000 feet above sea level; set at 15 pounds pressure at higher altitudes. If using a dial-gauge canner; set at 11 pounds pressure at 0-2000 feet above sea level; 12 pounds at 2,001-4,000 feet; 13 pounds at 4,001-6,000 feet; 14 pounds at 6.001-8,000 feet; or 15 pounds above 8,000 feet.
7. Allow canner to cool and release pressure. Remove jars and set on towel on counter. Let rest until cool, or overnight. Remove rings, wipe any spills. Date and label and store in a cool, dry location, out of direct sunlight. Best used within 1-2 years.