Preheat oven to 275 degrees F (135 degrees C).
Coat the inside of an oven roasting bag with flour. Place brisket inside of bag. Pour liquid smoke over the brisket and sprinkle on garlic powder
dry onion soup mix
and ground black pepper. Seal bag. Using a fork
make two sets of holes in the top of the roasting bag.
Lay bag in a broiling pan. Bake in a preheated oven for 6 to 8 hours.