Preheat your oven to 350°F (175°C).

Grease a large baking dish generously with butter or cooking spray.

Whisk together 8 eggs, 2 cups of milk, and a tablespoon of Dijon mustard, along with garlic powder, onion powder, salt, and pepper.

Layer 4 cups of cubed English muffins in the dish and add 1 to 2 cups of diced ham or Canadian bacon.

Pour the egg mixture over the muffin and meat layers.

Cover the dish with aluminum foil and bake for 30 minutes.

After 30 minutes, uncover and bake for an additional 15-20 minutes until golden brown.

Prepare the Hollandaise sauce by whisking together 3 egg yolks and 1 tablespoon of lemon juice, then slowly add 1/2 cup of hot melted butter.

Serve the casserole hot with Hollandaise sauce and garnish with fresh chives.