Preheat your oven to 350°F (175°C). Grease a 9x13-inch pan with butter or nonstick cooking spray to prevent sticking and ensure easy cleanup.

In a large skillet over medium heat, cook the ground pork sausage until browned and cooked through, breaking it up into crumbles as it cooks. In the last few minutes of cooking, add the crushed red pepper flakes and stir to combine. Once finished, set the sausage aside.

In a heavy saucepan over medium-low heat, melt the butter. Whisk in the flour and cook the roux for several minutes, whisking constantly to avoid burning. Slowly whisk in the milk, then add the salt, onion powder, and ground black pepper. Simmer the sauce, whisking frequently until thickened. Stir in 1/2 cup of the cooked sausage mixture from Step 2 to complete the sausage gravy.

Cut each refrigerated biscuit into quarters and scatter the pieces in a single layer on the bottom of your prepared 9x13-inch pan. Evenly distribute the remaining browned sausage (from Step 2) over the biscuits, then sprinkle half of the shredded Colby Jack or cheddar cheese on top.

In a mixing bowl, whisk the eggs with the heavy cream until completely combined and smooth. Pour this mixture evenly over the casserole to help bind it together and create a fluffy texture as it bakes.

Pour the homemade sausage gravy (from Step 3) evenly over the top of the casserole. Sprinkle the remaining shredded cheese over the gravy layer. Bake uncovered in the preheated oven for 30-35 minutes, or until the casserole is puffed, lightly browned, and the eggs are set. I like to let the casserole rest for 5-10 minutes after baking; this makes it easier to slice and serve.