In saucepan, heat butter over medium-low heat. Chop onions and cook for 3 to 5 minutes until opaque. Stir in ketchup, sugar, Worcestershire sauce, steak sauce, vinegar, water, and hot pepper sauce. Bring to a boil; reduce heat and cook for 15 minutes, stirring occasionally. Using a brush or mop, apply to meat before and during the grilling or slow cooking process.