To prepare for water-bath canning:
- Wash jars and lids in hot soapy water; rinse with warm water.
- Fill canning pot half full of water; add jars and water to cover. Bring water to a boil, reduce heat and simmer.
- Place lids in water to cover in a small saucepan; bring water to a simmer. Simmer until ready to use.
- Remove and drain jars and lids, one at a time, as needed for filling.
To make the sauce:
- Fill a stock pot ¾ full of water; bring to a boil. Working in batches, add tomatoes and boil for 20 seconds or until skins easily peel away; remove with slotted spoon and transfer to ice water.
- Use a paring knife to slip skin off tomatoes; cut in half crosswise and squeeze out juice and seeds in a bowl. Pour juice through a mesh strainer and discard seeds. (There will be about 6 cups of tomato pulp and ¾ cup tomato juice). Cut tomatoes in chunks; place in food processor in batches and process until finely chopped.
- In a large, heavy stock pot, combine tomato pulp, juice, cumin, coriander and cayenne and bring mixture to a full rolling boil. Reduce heat; simmer, stirring occasionally, for 1 hour or until mixture thickens.
- Place tomato mixture in food processor in batches and process until smooth.
- Return to heavy stock pot and add Splenda Stevia Sweetener, lemon juice, and salt. Bring to a boil over medium heat. Boil for 1 minute, stirring constantly. Remove from heat; add Splenda Sweetener, stirring until sweetener dissolves. Skim off any foam.
To can the sauce:
- Ladle hot sauce immediately into prepared jars, leaving ½” of headspace at top of jars. Wipe jar rims and threads. Cover with 2-piece lids; tighten bands.
- Place jars on rack in canning pot. (Water must cover jars by at least 1”; add boiling water, if necessary.) Cover; bring water to a gentle boil.
- Process for 10 minutes. Remove jars and place upright on a towel to cool completely.
- After jars cool, check seals by pressing center of lid with finger. (If lid springs back, lid is not sealed and refrigeration is necessary.)
- Store in a cool, dark place for up to 1 year. Once opened, store refrigerated and use within 2 weeks.