Louisiana Roast Beef - cooking recipe

Ingredients

1/4 cup onion, chopped very fine
1/4 cup celery, chopped very fine
1/4 cup bell pepper, chopped fine
2 tablespoons unsalted butter
1 teaspoon salt
1 teaspoon white pepper
3/4 teaspoon black pepper
3/4 teaspoon garlic, Minced
1/2 teaspoon dry mustard
1/2 teaspoon cayenne, Ground
4 lbs boneless beef sirloin

Preparation

In a small bowl combine the onions, celery, bell peppers, butter and seasonings, mix well.
Place roast in a large roasting pan, fat side up.
With a large knife make 6 to 12 deep slits in the meat (to form pockets) down to a depth of about 1/2 inch from the bottom; do not cut all the way through.
Fill the pockets to their depths with the vegetable mixture, reserving about 1 tablespoon of the vegetables to rub over the top of the roast.
Bake uncovered at 300F until a meat thermometer reads about 160F for medium doneness, about 3 hours.
For rarer roast, cook until thermometer reads 140F.
Serve immediately topped with some of the pan drippings if you like.