In small skillet add the butter, raisins, and shallots. cook, stirring often, until shallot is soft, about 3 minutes. Add broth to skillet; increase heat and bring to a boil, scraping up browned bits from bottom of pan. Reduce heat to medium-low and simmer until broth has evaporated, 1–2 minutes. Stir in vinegar and crumbled bacon. Season to taste with salt and pepper.