Created by KittenCal on November 8, 2011
Step 1: Place the brisket in a greased roasting pan fat side up; stir together first 5 ingredients, then pour over brisket, sprinkle onion slices on top, then cover tightly with foil, and refrigerate 24-48 hours.
Step 2: When ready to cook the brisket, unwrap and season with black pepper (use lots!) return the foil over the roast; preheat oven to 323 degrees F, cook brisket covered for 4 to 4 1/2 hours or until fork-tender; remove the foil then transfer to a cutting board.
Step 3: Using a serrated or very sharp slicing knife (I use my electric knife) slice brisket across the grain into thin slices; transfer to a serving platter, then cover with foil and place in a preheated 150 degree oven to keep warm while preparing the sauce.
Step 4: Pour pan drippings through a wire-mesh strainer, then place into a large bowl; allow the fat to rise to the top (this should take about 15 minutes) then spoon off and discard -- serve brisket with drippings.