Preheat your oven to 350°F and grease a 9×13-inch baking dish thoroughly with butter or non-stick spray.

Pop open the refrigerated biscuit dough container. Use a sharp knife or kitchen shears to cut each raw dough disc into 4 equal quarters. Scatter the biscuit pieces evenly across the bottom of your prepared pan.

Crumble the pork breakfast sausage into a large skillet over medium-high heat. Sauté for 6 to 8 minutes, chopping the meat into small pieces, until it is completely browned and cooked through. Drain off any heavy pooled grease.

Scatter the hot, browned sausage crumbles directly over the raw biscuit pieces in the pan.

The Hydrophobic Cheese Layer: Sprinkle exactly half (1 cup) of the freshly shredded cheddar cheese directly over the warm sausage and biscuits. Pro Tip: Melting the first layer of cheese straight onto the raw dough creates a hydrophobic lipid barrier. This greasy cheese shield prevents the wet egg liquid and dense gravy from soaking straight to the core of the biscuits, ensuring the bottom dough rises up light and fluffy instead of collapsing into a gummy paste.

In a mixing bowl, combine the 6 eggs, ½ cup of whole milk, and a pinch of salt and black pepper. Whisk vigorously for 45 seconds until completely frothy and uniform. Pour this liquid custard evenly over the sausage and cheese layers.

In a small pot, whisk your country gravy mix with the liquid (water or milk) according to package directions over medium heat until it bubbles and thickens. Remove from heat and pour it uniformly over the top of the egg layer.

Blanket the top of the gravy with the remaining 1 cup of shredded cheddar cheese.

Bake uncovered for 30 to 35 minutes. The Set Test: Give the pan a gentle shake at the 30-minute mark; the center should be stable and free of fluid waves, and the exposed biscuit points pushing through should be a deep golden brown. Let the casserole rest on the counter for 5 to 7 minutes before slicing so the internal gravy thickens back to a sliceable texture.