Grease a 9x13-inch casserole dish with butter or nonstick spray.

Chop all the Canadian bacon into bite-size pieces. Spread half of it over the bottom of the dish.

Split the English muffins with a fork. Toast each half, spread it with butter, then chop the muffins into 1-inch pieces. Or spread each half with butter, chop the muffins, broil the pieces on an ungreased baking sheet for 1 to 2 minutes, then flip them and broil until toasty.

Add half of the English muffin pieces on top of the Canadian bacon. Repeat with the rest of the Canadian bacon, then the rest of the English muffins.

In a large bowl or stand mixer, whisk the eggs, 1 1/3 cups cream, 2/3 cup milk, kosher salt, seasoned salt, black pepper, onion powder, paprika and mustard powder until well mixed.

Sprinkle the Monterey Jack over the top if you are using it. Pour the egg mixture over the English muffins and Canadian bacon, spreading the liquid evenly.

Cover the dish well with foil and refrigerate overnight, or for at least 4 hours.

Take the casserole out of the refrigerator while the oven heats to 375°F, and keep it covered with foil. Bake for 35 minutes. Remove the foil and bake 10 to 15 minutes longer, until the center is set and not liquid-y and reads 160°F on a food thermometer. It may jiggle a little but should not slosh, and a butter knife in the center should come out with no wet egg on it.

Put the egg yolks, 1/2 cup cream, lemon juice, Dijon mustard, cayenne pepper and a dash of salt in a blender. Blend on high for at least 30 seconds.

Melt the 1/2 cup butter in the microwave for about 15 to 20 seconds, until it is mostly melted but not all the way, then stir until the last of it melts. It should be warm, not steaming hot. With the blender running, add the butter slowly through the small opening in the lid. Keep blending until all the butter is in and the sauce looks smooth and creamy.

Serve the hollandaise over the casserole, drizzled over individual portions or spooned over the whole dish.