Prepare biscuits according to package instructions but do not bake. Cut raw biscuits into 6 pieces each. Set aside.
Place sausage, bell pepper, and onion in a large skillet over medium heat, crumbling sausage and cooking until no longer pink. Drain and transfer mixture to a lightly greased 13x9 inch (or similar) baking dish.
Prepare gravy according to package instructions.
Whisk eggs in a mixing bowl with salt and pepper. Pour over sausage mixture. Sprinkle cheese over top. Pour half of gravy on top of cheese.
Arrange biscuit pieces on top and bake until biscuits are golden brown and casserole is bubbly, about 30 minutes.
Remove casserole from oven and brush biscuits with melted butter. Sprinkle with dried sage. Serve warm and top with additional gravy if desired.