Mix together all ingredients except soy sauce and butter. Simmer in a sauce pan for approximately 10 minutes, then remove from heat and stir in soy sauce and butter.
This sauce is great with pulled pork shoulder or as a finishing sauce on
pork ribs.
Mix the chili powder, black pepper, sugar, and salt in a bowl. In a large saucepan, whisk the ketchup
and mustard into a smooth mixture. Stir in the Worchestershire sauce, vinegar, and spice mixture and
cook over medium heat for 10 minutes. Reduce heat to low and add butter. Simmer the sauce until the
butter is melted. Taste the sauce - if it's too tart add some brown sugar and simmer another 5 minutes.
Serve warm.