Preheat the oven to 350°F (175°C) and grease a baking dish.

In a large mixing bowl, whisk the eggs until frothy and then add the milk, salt, black pepper, cayenne pepper, and Dijon mustard, mixing well.

Layer the quartered English muffins at the bottom, followed by the Canadian bacon, then pour the egg mixture over the top and add the cheddar cheese.

Cover with aluminum foil and bake for 30 minutes. Remove foil and bake for another 15-20 minutes until golden brown.

Let the casserole cool for 5-10 minutes, then drizzle with hollandaise sauce and garnish with chives or parsley before serving.