For the best keto results, choose a breakfast sausage with no added sugar or starchy fillers and stick with full-fat cheese and heavy cream for maximum flavor and satisfaction. You can swap the red bell pepper for green bell pepper or omit it to reduce carbs slightly, and the spinach can be replaced with chopped kale or left out if you prefer a simpler muffin. Avoid overbaking to prevent a dry, rubbery texture by removing the muffins when the centers still have a slight jiggle, as they will continue to set while resting in the pan. Serve with sliced avocado, a spoonful of sour cream, or a dash of hot sauce to boost fat and add extra flavor while keeping carbs low.