Start by greasing a 9x13-inch baking dish with non-stick cooking spray or butter.

In a large mixing bowl, whisk together six eggs, 2 cups of milk, and chopped green onions until thoroughly blended. Sprinkle in the onion powder and a pinch of salt, stirring until smooth.

Layer half of the Canadian bacon, followed by half of the toasted English muffins cut into pieces in the greased baking dish. Pour the prepared egg mixture evenly over the layers, ensuring every piece is soaked. Top with remaining Canadian bacon and muffin pieces.

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

Preheat your oven to 375°F (190°C), remove the cover, sprinkle paprika over the top, cover loosely with foil, and bake for 30 minutes. Uncover and bake for an additional 15 minutes or until set and lightly golden.

In a saucepan over medium heat, combine the hollandaise sauce mix, 1 cup of milk, and 1/2 cup of butter. Whisk continuously for about 1 minute until the sauce thickens and becomes creamy.

Once baked, remove from the oven and let sit for a few minutes before slicing. Drizzle warm hollandaise sauce over each serving.