brisket (I like flat brisket - less fat)

Claude's Barbeque Brisket Marinade Sauce  (in Wal Mart, Claude's is with the barbecue sauces on the mayonnaise aisle)

Reynold's Large Size Oven Bag

The day before, place brisket in oven bag in baking pan and liberally pour marinade over.  The Claude's bottle will tell you approximately how much.  Position brisket so that fat side is on top.  This way the fat will baste the meat as it cooks.  Refrigerate until ready to bake. 

Preheat oven to 300 degrees.  Cut six slits, about 1/2 inch each, in top of bag to allow steam to escape.  Bake for approximately 4 hours.

Serve with horseradish sauce, if desired.