In a large saucepan, bring 8 cups water to a boil. Add asparagus, cover and cook for 3 minutes. Drain and immediately place asparagus in ice water. Drain and pat dry.
Arrange 6 Englich muffin halves, cut sides up, in a greased 9x13 inch baking dish. Fill in the spaces with the remaining muffin halves.
Sprinkle with 1 cup of the cheese, asparagus, ham and red pepper.
In a bowl, whisk eggs, milk, salt, mustard and pepper. Pour over the muffins. Cover and refrigerate overnight.
Remove from refrigerator 30 minutes before baking. Sprinkle with the remaining cheese.
Bake uncovered at 375 degrees F for 40-45 minutes or until a knife inserted in the center comes out clean. Let stand 5 minutes before cutting.