½ cup white sugar
⅜ cup brown sugar (packed)
⅔ cup vegetable stock
2 tablespoons molasses
1 quart hot water
⅔ cup yellow mustard (ball-park)
⅓ cup red wine vinegar
⅓ cup liquid smoke (hickory)
⅔ cup Worcestershire sauce (142ml bottle)
1 ⅓ cup tomato paste (300ml can)
1 to 1 ½ tablespoons red pepper flakes (cayenne)
1 to 2 Serrano peppers (seeded and very finely diced)
Mix sugars and stock with hot water in large pot. Heat until completely dissolved, stirring occasionally. Add remaining ingredients. Simmer very gently for 3 to 4 hours over low heat until thick and reduced by half to three-quarters, stirring infrequently. Strain when cool.