Adding my method for making and (water-bath) canning a shelf-stable roasted tomato puree:
Core and halve the tomatoes across the equator (not pole-to-pole), scooping out the seeds and gel with your thumbs/fingers. No need to be perfect - removing most is good enough. Place the tomatoes in a crammed, single layer cut-side up on a rimmed sheet-pan. DO NOT ADD OIL. Roast at 325 for 2-3 hours until black spots appear.
Puree the roasted tomatoes in a food processor until smooth. In a large pot, bring the puree to a boil, thinning to the consistancy of a commercial sauce with 100% tomato juice (store bought or homemade). Hot-pack the pint jars, adding 1 T. bottled lemon-juice (and optional 1/2 t. kosher salt) to each pint jar. Leave 3/4" head space and process in the canner for 40 minutes.
If you’re concerned about acidity levels, you can use PH testing strips here to determine acidity levels. Add lemon juice, if needed.
The residue on the sheet pans comes off easily with a quick wash.
From two full 1/2 sheet pans + 64 oz. tomato juice, I typically get a full canner load of 7 pints.
