Cut 3–4 pounds of steak into 1-inch pieces, trimming and discarding any excess fat or gristle as you go.
Arrange the steak pieces in a single layer across the bottom of a crockpot.
Sprinkle 1 packet of au jus gravy mix and 1 packet of onion soup mix evenly over the steak. Lay 4 tablespoons of butter (cut into pats) on top of the seasoned steak. Pour 1 cup of beef broth over everything.
Place the lid on the crockpot and cook on low for 4–6 hours, or on high for 3–4 hours. For the most tender results, pull closer to the lower end of the cook time.
Serve steak bites with the au jus from the bottom of the crockpot spooned over the top. Garnish with chopped fresh parsley if desired.