Pepperoncini Beef

Name: Pepperoncini Beef
Total time: 2100 s
Yield: 4 servings
Ingredients: 5 pounds chuck roast; 12 ounces beers; 1 cup worcestershire sauce; 2 tablespoons gravy master; 2 teaspoons salt and ground black pepper kosher; 1 cup marinade reserved; 16 ounces pepperoncini peppers and their juice; 1 tablespoon minced garlic; 2 red onions large; 2 tablespoons extra-virgin olive oil; 2 tablespoons butter; 2 teaspoons brown sugar; 1/2 teaspoon salt and ground black pepper each of kosher