For best texture, finely chop the bell pepper and onion so they cook through quickly and distribute evenly in each muffin. Use a sugar-free sausage without added fillers or sweeteners to keep the muffins strictly keto. To reheat from the refrigerator, warm the muffins in the microwave for about 20 to 30 seconds, or in a 350°F oven for about 10 minutes for a firmer, slightly crisp edge. From frozen, thaw overnight in the refrigerator or reheat gently in the microwave for 1 to 2 minutes until warm in the center. These muffins pair well with sliced avocado or a simple green salad for a complete keto meal.