Use a sugar-free breakfast sausage with clean ingredients to keep this casserole strictly keto and avoid hidden sugars or fillers. For easy meal prep, bake the casserole fully, cool it, and store slices in airtight containers in the refrigerator for up to 4 to 5 days or in the freezer for up to 2 months. Reheat individual portions in the microwave or in a 300°F oven until warmed through. You can customize the flavor by swapping cheddar for a Mexican blend or pepper jack and adjusting the spices to taste. If adding extra low-carb vegetables, keep the amounts moderate so the net carbs per serving stay keto-friendly.