Heat a large skillet over medium-high heat and add the ground sausage, breaking it apart with a spoon as it cooks until fully browned and no pink remains, about 5-7 minutes. Once cooked, reduce heat to medium and add the butter directly to the skillet with the sausage, allowing it to melt completely. Sprinkle the flour over the mixture and stir constantly for 1-2 minutes to cook out the raw flour taste and create a paste-like base—this is your roux, which will thicken the gravy. I like to cook the roux a bit longer than most recipes call for; it deepens the flavor and prevents any floury taste in the final dish.

Slowly pour the milk into the roux while stirring constantly to prevent lumps from forming. Continue stirring as the mixture heats through and comes to a gentle boil, which typically takes 3-4 minutes. Once boiling, reduce heat to low and let the gravy simmer for 2-3 minutes until it thickens to a pourable but creamy consistency. Stir in the garlic powder, Worcestershire sauce, salt, and black pepper to taste. For a richer, more luxurious gravy, I add the heavy cream at this point rather than later—it creates better flavor development when incorporated into the base.

While the gravy simmers, spray the crockpot with cooking spray to prevent sticking. In a bowl, beat the room-temperature eggs together until well combined—room temperature eggs mix more smoothly and distribute more evenly throughout the casserole. Cut the refrigerated biscuits into quarters so they'll cook through evenly in the crockpot. Pour half of the prepared gravy into the bottom of the crockpot, spreading it evenly.

Arrange half of the biscuit pieces (approximately 12 pieces) over the gravy layer in a somewhat even distribution. Pour the beaten eggs over the biscuits, allowing them to settle into the gaps. Add the remaining gravy over the egg layer, then top with the remaining biscuit pieces. The layering ensures that each component cooks evenly and the eggs distribute throughout the casserole rather than settling at the bottom.

Cover the crockpot and cook on low for 2 to 2.5 hours, until the eggs are set and the biscuits are cooked through. The casserole will bubble gently around the edges and the biscuits will absorb the gravy while staying tender. Let it rest for 5 minutes before serving—this helps the casserole set slightly and makes it easier to scoop onto plates.