1. In a ziptop bag, add silan, mustard, garlic, pomegranate juice, chili powder, salt, black pepper, and chicken consommé. Mix around in the bag to combine. Then add brisket to the marinade, remove air, and seal. Marinate for at least two hours or overnight.
2. Preheat the oven to 325 degrees Fahrenheit.
3. In a large, flat pot or skillet, heat the olive oil. Add the thinly sliced onions and cook until translucent. Remove half of the onions and set aside into a Pyrex dish that has been sprayed with oil.
4. Add the brisket to the pot and reserve the bag with the marinade. Cook brisket with remaining onions for five minutes on each side, until a slight crust forms. Then remove brisket from pot and place into Pyrex dish. Add onions from the pot on top so that you have half the onions below the brisket and half on top. Pour remaining marinade over brisket and onions along with chicken stock.
5. Cover tightly with foil and place in oven for three hours. Remove and let cool completely either for one hour or overnight before slicing against the grain.