Heat a large skillet on medium-high heat. Butter the insides of the English muffins and toast until golden brown. Remove and set aside.
Portion and flatten sausage into 6 large patties. Cook the patties on both sides in the same large skillet on medium high heat until cooked through. Transfer to plate and set aside.
For the egg frittata, to a blender or food processor, combine eggs, cream cheese, Monterrey Jack, salt and pepper. Blend until smooth.
Pour the egg mixture in a non-stick sprayed microwave safe baking dish. Microwave 3 minutes, stir, then microwave an additional 1-2 minutes or until the eggs are set. Slice into 6 squares.
Build your sandwiches starting with the bottom English muffin bread slice followed by the sausage patties, egg square, cheese slice, then the top bread slice.
Individually wrap in wax paper or Ziploc bags. When ready to eat, heat in the microwave for 1 minute or air fry at 400° for 4-5 minutes.