Toast the English Muffins and cut into 1/2 inch dice.
Cut up Canadian bacon and fry until slightly crisp.
Spray 9 x 13 inch baking dish with cooking spray.
Whisk eggs, 2 cups of milk, green onions, onion powder and salt together in a large bowl until well mixed.
Layer half the fried Canadian bacon in the prepared baking dish. Spread toasted English muffins over meat and top with remaining Canadian bacon. Pour egg mixture over casserole. Cover baking dish with plastic wrap and refrigerate overnight.
Next day, Preheat the oven to 375 degrees F.
Sprinkle casserole with paprika, cover with aluminum foil.
Bake until eggs are nearly set, about 30 minutes; remove foil and continue baking until eggs are completely set, about 15 minutes.
Whisk hollandaise sauce mix with 1 cup milk in a saucepan. Add butter and bring to a boil, stirring frequently. Reduce heat to medium-low, simmer and stir until thickened, about 1 minute. Drizzle sauce over casserole to serve.