Brown the turkey sausage in a spacious skillet over medium-high heat, cooking thoroughly until no pink remains. Incorporate the butter, stirring until it melts completely, then sprinkle in the flour and garlic powder, mixing well to form a smooth blend. Gradually pour in the milk, stirring steadily with a wooden spoon until the gravy thickens to your preference. Adjust the seasoning with salt and freshly ground black pepper as needed. Serve generously over warm, flaky biscuits.