This recipe is from my Brother in law, David Rose.  I often cook a whole 10-14 lb brisket (trim the some of the excess fat an untrimmed whole brisket) and double or triple the sauces.

Ingredients:
1 4-5 lb beef brisket (for a larger brisket, double or triple the sauces)

Sauce #1
4 t. Worcestershire sauce
2 T. Liquid smoke
4 T. Soy sauce
2 t. garlic powder with salt
2 t. onion Salt
2 t. black pepper
2 t. salt
dash of Tabasco to taste

Sauce #2
6 T. dark brown sugar
1 cup ketchup
2 t. dry mustard
2 t. lemon juice
2 T. Soy Sauce
1/2 t. nutmeg
dash of Tabasco to taste

Preparation:
Mix all of the ingredients for Sauce #1 and let stand 20 minutes.

Place Brisket in a deep roasting pan and cover with Sauce #1. Cover brisket with foil. Bake for 3 hours at 300 degrees.

Mix all of the ingredients for Sauce #2 and let stand for 20 minutes.

After brisket has baked for 3 hours, pour off about half of the drippings. Cover with Sauce #2 and cook another 1&1/2 hours, covered with foil.

Let Brisket set for about 30 minutes before slicing.