Preheat your oven to 375°F (190°C) and grease a 9x13-inch casserole dish with cooking spray and set aside.

In a mixing bowl, combine the Bisquick, milk, egg, and half of the black pepper until smooth. Pour the Bisquick mixture into the prepared baking dish.

In a large skillet over medium-high heat, brown the ground beef, about 5-7 minutes.

Add the onion slices and green bell pepper slices to the skillet with the beef and cook until softened, about 5-7 minutes. Drain any excess grease.

Stir the brown gravy mix, water, and the remaining black pepper into the ground beef mixture. Simmer for about 3-5 minutes until the liquid is reduced.

Spread the beef mixture over the Bisquick. Top with the cheese slices, spacing evenly and tearing the slices as needed for full coverage.

Bake the casserole in the preheated oven for 25-30 minutes, or until the layer of provolone cheese is golden brown and a toothpick inserted in the biscuit layer comes out clean. If the cheese becomes too brown before the biscuit layer is done cooking, cover the top of the casserole in aluminum foil.

Allow the casserole to cool for about 10 minutes before slicing and serving.