Begin by cutting the English muffins into bite-sized cubes and toasting them until golden brown, about 5-7 minutes in a toaster or oven. Layer the cubes into a greased baking dish.

In a large mixing bowl, whisk together 12 eggs, 2 cups of heavy cream, and seasonings like salt, pepper, and nutmeg until smooth.

Pour the egg mixture over the toasted English muffins, ensuring every piece gets well-coated. Distribute diced ham and chopped green onions evenly over the top.

Cover the casserole tightly with plastic wrap or aluminum foil and refrigerate for at least 8 hours.

Preheat your oven to 350°F (175°C). Bake for 40-50 minutes until puffed and golden brown. Insert a knife into the center to check for doneness.

Prepare your hollandaise sauce while the casserole is baking, then drizzle it over the casserole upon serving.