01 - Grease a 9x13-inch baking dish. Scatter half of the English muffin pieces evenly in the dish. Top with half of the Canadian bacon. Repeat layers with remaining muffins and bacon.
02 - Whisk together eggs, milk, salt, black pepper, Dijon mustard, and paprika in a large bowl. Pour mixture evenly over the muffin and bacon layers. Press gently to ensure bread absorbs the liquid.
03 - Cover and refrigerate for at least 1 hour, or overnight for optimal results and deeper flavor development.
04 - Preheat oven to 375°F.
05 - Remove from refrigerator while oven heats. Bake uncovered for 40-45 minutes until the center is fully set and the top is golden brown.
06 - In a heatproof bowl over a pot of gently simmering water, whisk together egg yolks, lemon juice, Dijon mustard, salt, and cayenne. Slowly drizzle in melted butter, whisking constantly until thickened and smooth. Remove from heat.
07 - Let the baked casserole rest for 10 minutes. Slice and serve warm, drizzled generously with hollandaise sauce. Garnish with fresh chives or parsley if desired.