01 - Preheat oven to 375°F. Grease a 9x13-inch baking dish with butter or cooking spray.
02 - Spread English muffin pieces evenly in the prepared dish. Top with diced Canadian bacon.
03 - Whisk together eggs, milk, salt, and black pepper in a large bowl until well combined.
04 - Pour egg mixture evenly over muffins and bacon. Cover with foil and refrigerate at least 1 hour or overnight.
05 - Remove from refrigerator while oven preheats. Sprinkle with paprika. Bake covered for 30 minutes.
06 - Remove foil and bake 15–20 minutes longer until center is set and top is golden brown.
07 - Whisk egg yolks, lemon juice, salt, and cayenne in a heatproof bowl over simmering water for 2–3 minutes until thickened. Slowly drizzle in warm butter while whisking constantly until thick and glossy.
08 - Let casserole rest 10 minutes before slicing. Serve warm topped generously with hollandaise sauce.