9–10 lbs. Roma tomatoes, rinsed
3 small whole heads of garlic
2 medium onions, small diced (about 1 cup)
1 tsp. olive oil
1 tbsp. fresh oregano, minced
2 tbsp. fresh basil, minced
1 tsp. salt
½ tsp. coarsely ground black pepper
Citric Acid or bottled lemon juice
Slice top portion off the heads of garlic, revealing the cloves below, drizzle 1 teaspoon olive oil over cloves in each head. Wrap garlic tightly in aluminum foil and roast in a 350° oven for 60 minutes.
After garlic is baked, turn oven onto broil, and position rack 6 inches away from heat source.
Core tomatoes, and cut in half lengthwise. Place tomatoes cut side down on a parchment-lined baking sheet, squeezing in as many as you can fit in a single layer. Roast tomatoes in batches until skins begin to wrinkle and blacken slightly, approximately 8-10 minutes, depending on oven heat. Allow tomatoes to rest in sheets until cool until to handle.
Once cool enough to handle, slip off skins and discard. Remove seeds; dice into 1-inch chunks. Alternately, pass tomatoes through a tomato press to remove skin and seeds. Place diced tomatoes or tomato puree into a large saucepan.
Prepare a boiling water canner. Prepare clean jars by either simmering in water until ready to use or run them through the dishwasher and leave the door closed until ready to fill so the jars are still warm. Wash lids in warm soapy water and set aside with bands.
Remove roasted garlic by squeezing the softened heads of garlic, allowing the cloves to pop out into a small bowl. Add a ¼ cup or so of the tomato juices and whisk until garlic is evenly combined to avoid any lumps of garlic in the sauce. Combine garlic, onions, herbs, salt and pepper with tomatoes. Cook over medium heat until heated through, stirring occasionally. If sauce isn’t thick enough to your liking, continue to simmer, stirring occasionally for an additional 30-60 minutes to further reduce the sauce.
Add ½ teaspoon citric acid or 2 tablespoons lemon juice to a hot jar; ladle hot sauce into a hot jar leaving a ½ inch headspace. Remove air bubbles. Wipe jar rim. Center lid on jar and apply band, adjust to fingertip tight. Place jar in boiling water canner. Repeat until all jars are filled.
Process jars 40 minutes, adjusting for altitude. Turn off heat, remove lid, let jars stand 5 minutes. Remove jars and cool 12-24 hours. Check lids for seal, they should not flex when center is pressed.