1. Heat oven to 425ᵒF. Roast pork tenderloin about 20 to 30 minutes per pound until internal temperature reaches 150ᵒF. Let stand 10 minutes before slicing.
2. Meanwhile, sauté onions in butter over medium-high heat until browned and tender. Add wine and garlic; continue cooking until wine has evaporated.
3. Whisk in cream and Worcestershire sauce. Stir in blue cheese until melted. Remove from heat and season with fresh ground pepper.
4. Let stand at room temperature to thicken before serving over sliced tenderloin.