1.Mix together all of the spices and rub onto the flank steak
2.Heat a grill or skillet over medium high heat. Drizzle grates with olive oil or heat in skillet.
3.Grill or sear the steak for 2 minutes on each side
4.Add to the slow cooker. Pour beer and stock over top. Cook on low for 8 hours until tender. Slice up and enjoy!