Set oven to 325 degrees (oven rack set to second-lowest position).
Generously spray 12 regular-size muffin tins with cooking spray.
Heat oil in a large skillet over medium heat.
Add in the sausage meat and cayenne pepper (if using) and cook breaking up meat with a spoon into very small pieces; cook for about 10 minutes or until the meat is browned, transfer to a large bowl.
Add in butter to the skillet; add in sliced mushrooms and cook for about 7-10 minutes or until browned; remove the mushrooms to the bowl; cool then chop into small pieces and add to the bowl with the cooked sausage meat.
Add in the Swiss cheese and Parmesan cheese, finely chopped green onion, black pepper and seasoned salt to the sausage/cheese mixture; mix to combine.
In a bowl whisk eggs, egg whites and half and half cream together until blended.
Divide the egg mixture between each muffin tin.
Sprinkle about 2 tablespoons sausage mixture on top of the egg mixture.
Bake for about 25 minutes or until the tops are just beginning to brown.
Let cool for 5 minutes in the tins.
Place a rack on top of the pan, then flip it over and turn the quiches out onto the rack.