4 Large onions - chopped
3 Tablespoons vegetable oil - for sauteing
1 28 Oz Can tomato puree
3 28 Oz Cans tomatoes - with juice
2 1/2 Cups white vinegar
4 Tablespoons packed dark brown sugar
4 Tablespoons granulated sugar
2 Tablespoons salt
2 Tablespoons freshly cracked black pepper
2 Tablespoons paprika
2 Tablespoons chili powder
4 Tablespoons molasses
1 Cup orange juice
2 Tablespoons Liquid Barbecue SmokeR
8 Tablespoons brown mustard - Dijon-style
1.In a large, heavy-bottomed saucepan, saute the onion in the oil over medium-high heat until golden brown, about 7 to 10 minutes.
2.Add all the remaining ingredients, bring to a boil, then reduce the heat and simmer uncovered at the lowest possible heat for 4 hours. (This long cooking removes as much acidity as possible from the tomatoes.)
3.Puree sauce in 2, 3, or more batches to prevent it from spilling out of your food processor or blender.
4.Will keep 2 weeks, covered, in the refrigerator.