Louisiana Roast Beef

Preheat oven to 300°F (150°C)

In a small bowl combine finely chopped onions, finely chopped celery, chopped green bell peppers, melted butter, pepper, minced garlic clove, dry mustard, and cayenne pepper. Mix well.

Place a beef sirloin roast in a large roasting pan, fat side up. Make 6 to 12 deep slits in the meat to form pockets down to a depth of about 1/2 inch from the bottom; but do not cut through. Fill the pockets with the vegetable mixture.

Bake uncovered in the oven for about 3 hours, or until a meat thermometer reads about 160°F (70°C). For rarer roast, cook until the thermometer reads 140°F (60°C).