Preheat the oven to 350°F (175°C). Lightly grease a 9×13-inch baking dish with nonstick cooking spray and set aside.

Cook the sausage in a large skillet over medium heat, breaking it into crumbles as it cooks. Continue until the sausage is browned and fully cooked. Drain and discard excess grease.

Prepare the sausage gravy by reducing the heat to medium. Add the two packets of gravy mix directly into the skillet with the cooked sausage. Pour in 1 cup of evaporated milk and 1 cup of water. Stir the mixture continuously until thickened, about 3 to 4 minutes. Remove from heat.

Scramble the eggs by whisking the 12 eggs in a large mixing bowl. Add 5 ounces of the remaining evaporated milk and season with salt and pepper to taste. Heat a nonstick skillet over medium heat and scramble the eggs until they are just set but still soft. Remove from heat.

Assemble the breakfast bake by layering ⅓ of the sausage gravy into the bottom of the prepared baking dish. Add half of the scrambled eggs over the gravy. Repeat the layers once more (gravy, eggs), and then top with the remaining gravy as the final layer.

Top with biscuits by placing the uncooked biscuit dough evenly across the top of the layered mixture.

Bake for 20–25 minutes, or until the biscuits are golden brown and cooked through. Allow the dish to rest for 5 minutes before serving.