Pretty quick and easy. I have it in the oven right now. Made it last week. Tasty.

Marinated Roast Beef Ingredients
8 pounds Rump Roast, trimmed 1/4 cup Worcestershire sauce
1 cup vegetable oil 1/4 cup mustard
3/4 cup soy sauce 30 cloves garlic cut in half
1/2 cup lemon juice 1 tablespoon Pepper, black fresh ground