• Fill a large pot or Dutch oven half-way with water, bring to a boil. Using a slotted spoon, add tomatoes one at a time until you can't fit any more (about 8-10 tomatoes). 
  
• Boil for 1-2 minutes. Remove tomatoes one at a time with slotted spoon and plunge in an icewater bath. Peel and quarter tomatoes.

  Note: I get a LOT of questions about if the tomatoes need to be peeled and seeded. I always peel the tomatoes and remove the rough stem area but they don’t need to be seeded. If you prefer to remove the seeds you certainly can though. If you decide to leave the skins on, it won’t change the acidity but it will change the texture and appearance.
  
• In a food processor, cover and process peppers and onions in batches until finely chopped (if you want to add extra flavor, saute the peppers and onions in a little oil and a pinch of salt before processing).

  In a large stockpot, combine the tomatoes (do not discard excess juices from the tomatoes), onion/pepper mixture, tomato paste, soy sauce, Worcestershire sauce, brown sugar, salt, garlic, oregano, basil, pepper flakes, and bay leaves.
  
• Bring to a boil. Reduce heat; simmer, uncovered, for 4-5 hours, stirring every 15 minutes or so (tomatoes burn easily so keep an eye on it). Discard bay leaves.

  If you want to make your sauce thick and smooth, use an immersion blender to blend the tomatoes until smooth with no large chunks (you can also blend it in batches in a blender). 
  
• Add 2 tablespoons lemon juice to each jar. This typically yields 8 to 10 hot 1-quart jars (depending on how much sauce you have and how much it is reduced when simmering). If using pint jars, use 1 tablespoon of lemon juice per jar.

  Ladle hot mixture into jars, leaving 1/2-in. headspace at the top. Remove air bubbles; wipe rims and adjust lids.

  Do not forget the lemon juice! If you forget to add the lemon juice you will need to open the jars, add the juice, replace with new lids, and reprocess.
  

For Water Bath Canning:

• Process for 40 minutes in a boiling-water canner for altitudes of 1,000 feet or less. For altitudes up to 3,000 feet, add 5 minutes; 6,000 feet, add 10 minutes; 8,000 feet, add 15 minutes; 10,000 feet, add 20 minutes.
  

For Pressure Canning:

• Using a weighted-gauge pressure canner, process 20 minutes for pint jars and 25 minutes for quart jars. Use 11 pounds pressure up to 2,000 feet elevation, increasing by 1 pound for every 2,000 feet (12 lbs for 2,001–4,000 ft, 13 lbs for 4,001–6,000 ft, and 14 lbs for 6,001–8,000 ft).