1. Chop onion into rings. Spread on bottom of crockpot. 2. Place chuck roast on top of onions. 3. Fill pot with enough broth or water to come 1/3-1/2 of the way up the sides of the roast. Use more if you know you will be away all day from it. 4. Season with pepper. 5. Cook low 6-8 hours or high for 2 hours and low for 2-4 hours, til easily shreddable. 6. For extra flavor melt butter on skillet and crisp hoagie rolls in them face down. 7. Pile meat onto buns, top with cheese and broil til brown and bubbly. 8. Top with liberal amounts of cilantro. 9. Serve with jus (juice) on the side.