Heat the oven and lay down the biscuits: Heat the oven to 350°F and grease a 9x13 baking dish. Cut each raw biscuit into 6 pieces and scatter them across the bottom of the dish in an even single layer, leaving small gaps between them.

Brown the sausage: Cook the sausage in a large skillet over medium heat for 8-10 minutes, breaking it into small crumbles, until no pink remains and it reaches 160°F. Leave the sausage and its drippings in the pan.

Build the gravy: Add the butter to the skillet and let it melt into the drippings. Sprinkle the flour over the sausage and stir constantly for 1-2 minutes, until the flour disappears and smells toasty. Pour in the milk about a third at a time, whisking smooth after each addition, then simmer 3-5 minutes until the gravy coats the back of a spoon. Stir in the salt, black pepper, onion powder and red pepper flakes if using.

Whisk the eggs: Beat the eggs with the heavy cream and garlic powder in a bowl until no streaks of white remain.

Layer the pan: Pour the egg mixture evenly over the biscuit pieces, letting it run down into the gaps. Sprinkle 1 cup of the cheddar over the eggs, then spoon the sausage gravy across the top in an even layer.

Bake: Bake uncovered for 35-40 minutes, until the center no longer jiggles when you nudge the dish and a thermometer in the middle reads 160°F. If the biscuit pieces underneath still look raw and shiny, give it another 5-10 minutes.

Finish with cheese and rest: Scatter the remaining 1 cup of cheddar over the top and return the dish to the oven for 5 minutes, until melted. Let it stand 5-10 minutes before cutting, then top with the chives.