Prepare the baking dish by spraying a 9x13-inch baking pan with non-stick cooking spray.

Layer half of the diced Canadian bacon evenly in the pan, followed by the cut English muffins, and then the remaining Canadian bacon.

In a large mixing bowl, whisk together the eggs, whole milk, onion powder, garlic powder, paprika, and a pinch of salt until smooth.

Pour the egg mixture over the layered ingredients, pressing down on the muffins to absorb the liquid.

Cover the dish and refrigerate for at least 5 hours or overnight.

On baking day, let the casserole sit at room temperature for 30 minutes.

Preheat the oven to 375°F (190°C). Cover the baking dish with foil and bake for 35 minutes.

Uncover and bake for an additional 15 minutes or until puffed and golden brown.

Prepare the hollandaise sauce by blending egg yolks, heavy cream, lemon juice, Dijon mustard, cayenne pepper, and salt until smooth.

Slowly drizzle in melted butter while blending until creamy.

Slice the casserole, serve warm, drizzled with hollandaise sauce, and garnish with chives.