Step 1: Prepare the Casserole
1. Preheat Oven: Preheat your oven to 350°F (175°C).
2. Layer Ingredients: In a greased 9×13-inch baking dish, layer the toasted English muffin halves, cut side up. Sprinkle the diced Canadian bacon evenly over the muffins.

Step 2: Mix the Egg Mixture
1. Whisk Eggs: In a large bowl, whisk together the eggs, milk, Dijon mustard, salt, and black pepper until well combined.
2. Pour Over Muffins: Pour the egg mixture over the layered muffins and bacon. Press down gently to ensure the muffins absorb the egg mixture.
3. Add Cheese: Sprinkle the shredded cheese evenly over the top.

Step 3: Bake the Casserole
1. Bake: Cover the dish with aluminum foil and bake in the preheated oven for 30 minutes. Remove the foil and bake for an additional 15 minutes, or until the casserole is set and the top is golden brown.

Step 4: Prepare the Hollandaise Sauce
1. Whisk Egg Yolks: In a heatproof bowl, whisk together the egg yolks and lemon juice until the mixture is pale and thick.
2. Melt Butter: In a small saucepan, melt the butter over low heat.
3. Combine: Gradually whisk the melted butter into the egg yolk mixture, continuing to whisk until smooth and creamy. Season with salt and cayenne pepper to taste.

Step 5: Serve
1. Garnish: Once the casserole is baked, let it cool for a few minutes. Drizzle the hollandaise sauce over the top and garnish with fresh chives or parsley if desired.
2. Enjoy: Slice and serve warm. Enjoy your delicious Eggs Benedict Casserole!