Beef Brisket with Sweet Garlic and Caramelized Onions

For Brisket:

Preheat oven to 350 degrees. Line a large shallow roasting pan with enough foil to completely wrap brisket. Mince 2 cloves of the garlic. Transfer garlic to a small bowl and mix in mustard, paprika, salt and pepper. Rub mixture all over brisket. Spread half of the onions and 6 garlic cloves in the bottom of the prepared pan. Place brisket over and top with remaining onion and garlic. Pour broth into bottom of pan. Seal brisket in foil. Bake until beef is tender, about 4 hours. Refrigerate brisket at least 6 hours or overnight.

For Onions:

Melt butter in a large skillet. Add onions and sugar and cook until onions are caramelized, stirring occasionally, about 20 minutes. Stir in pepper.

For Sauce:

Discard fat from brisket and remove brisket from roasting pan. Transfer onions and garlic from roasting pan to a food processor. Add flour and process until smooth. Add 1 cup juices from roasting pan, tomato paste, vermouth and mustard and process until smooth. Transfer sauce to a medium skillet. Add remaining juices from roasting pan and cook until slightly thickened, stirring frequently, about 5 minutes. Whisk in butter 1 piece at a time.

Preheat oven to 350 degrees. Thinly slice brisket and arrange in a large baking dish. Pour sauce over. Tent brisket with foil and bake until hot, about 30 to 40 minutes. Uncover and spread onions over brisket. Bake 10 minutes.