Preheat your oven to 375°F (190°C). Grease a 9x13 baking dish.
In a large skillet, cook the sausage over medium heat until browned and crumbled. Do not drain the grease.
Sprinkle flour over the cooked sausage and stir until well coated. Cook for 1-2 minutes to eliminate the raw flour taste.
Gradually pour in the milk, whisking constantly, and cook until the mixture thickens into a creamy gravy. Add garlic powder, onion powder, black pepper, and salt to taste. Remove from heat.
Open the can of biscuits and cut each biscuit into quarters.
Spread half of the biscuit pieces evenly on the bottom of the prepared baking dish.
Pour the sausage gravy over the biscuit layer, spreading it out evenly.
Top with the remaining biscuit pieces, arranging them over the gravy. Sprinkle shredded cheddar cheese on top, if desired.
Bake in the preheated oven for 25-30 minutes, or until the biscuits are golden brown and cooked through.
Let the casserole cool for 5-10 minutes before serving.