01 -
Heat a heavy-bottomed skillet over medium-high heat and add vegetable oil. Once hot, add beef stew meat in small pieces, season with black pepper, and sear each side for 1 to 2 minutes until browned but not cooked through. Remove from heat.
02 -
Spray the bottom of a 5-6 quart crockpot with non-stick spray. Arrange sliced onions evenly at the base.
03 -
Place the seared beef evenly over the onions. Sprinkle the Au Jus sauce mix over the beef, followed by the beef onion soup mix. Pour the can of French onion soup on top. Distribute sliced unsalted butter evenly over all ingredients.
04 -
Cover and cook on low for 4 to 6 hours, until the beef is tender and flavors meld.
05 -
Approximately 30 minutes before the end of cooking, sprinkle shredded mozzarella and provolone cheese evenly over the beef. Cover and allow the cheese to melt before serving.