Melt butter in medium size, heavy skillet over medium heat. Add bacon and cook, stirring often, until fat starts to render (about 3 minutes). Add onion and jalapeno. Cook until bacon is crisp and onion is soft and translucent (3-5 minutes). Stir in mustard, chutney, vinegar and coffee. Simmer, uncovered, until sauce is thick and rich (6-10 minutes). Season with salt and pepper.