01 - Preheat oven to 375°F. Grease a 9x13-inch baking dish with butter or cooking spray.
02 - Arrange English muffin pieces evenly in the prepared dish. Scatter diced Canadian bacon over the top.
03 - Whisk together 8 eggs, milk, 1/2 teaspoon salt, and black pepper in a large bowl until fully combined.
04 - Pour egg mixture evenly over muffins and bacon. Cover tightly with foil and refrigerate for at least 1 hour, or overnight for optimal results.
05 - Remove dish from refrigerator. Sprinkle paprika evenly over the surface. Bake covered for 30 minutes, then uncover and continue baking 15–20 minutes until center is set and top is golden.
06 - Set a heatproof bowl over gently simmering water. Whisk egg yolks, lemon juice, 1/4 teaspoon salt, and cayenne for 2–3 minutes until thickened. Slowly drizzle in warm butter while whisking constantly until sauce reaches glossy consistency.
07 - Let casserole rest 10 minutes before slicing. Serve warm topped generously with hollandaise sauce.