01 - Preheat your oven to 375°F. Grease a 9x13-inch baking dish with butter or cooking spray.
02 - Spread the English muffin pieces evenly in the prepared baking dish. Distribute the diced Canadian bacon over the muffins.
03 - In a large bowl, whisk together 8 large eggs, whole milk, 1/2 teaspoon salt, and 1/2 teaspoon black pepper until well combined.
04 - Pour the egg mixture evenly over the muffin and bacon. Cover with foil and refrigerate for at least 1 hour, or overnight for optimal results.
05 - Remove the casserole from the refrigerator while the oven preheats. Sprinkle paprika over the top. Bake covered with foil for 30 minutes.
06 - Remove the foil and continue baking for 15 to 20 minutes until the center is set and the top is lightly golden brown.
07 - While the casserole bakes, set up a double boiler with a heatproof bowl over gently simmering water. Whisk together egg yolks, lemon juice, 1/4 teaspoon salt, and cayenne pepper for 2 to 3 minutes until slightly thickened. Slowly drizzle in the warm melted butter while whisking constantly until the sauce becomes thick and glossy. Remove from heat.
08 - Let the casserole rest for 10 minutes before slicing. Serve warm slices topped generously with the freshly prepared hollandaise sauce.