- Preheat the oven to 375°F. Generously butter a 9 x 13 x 3-inch (deep) baking dish.
- Scatter the English muffin pieces across the prepared baking dish. Scatter the cubed butter on top, followed by the Canadian bacon.
- In a large bowl, whisk together the eggs, milk, cream, garlic powder, salt, and pepper. Pour the egg mixture over the bread and bacon, completely covering it.
- Cover with foil and bake for 30 minutes. Uncover and sprinkle the paprika on top. Bake until set and lightly browned, about 30 minutes.
- Meanwhile, make the hollandaise sauce: In a medium stainless-steel bowl or the top of a double boiler, combine the egg yolks, lemon juice, and 2 tablespoons of water. Nest the bowl over a pot of simmering water (the bowl should not touch the water) and whisk the mixture until the egg yolks thicken and double in volume. Whisking constantly, add the butter in a slow, steady stream. The sauce will thicken and increase in volume, 4 to 5 minutes. Add the cayenne and white pepper. Taste and add more lemon juice if needed.
- Remove the pan from the heat. Leave the bowl over the water to keep the sauce warm.
- Remove the casserole from the oven and pour over some warm hollandaise. Dust with some paprika and the parsley. Serve at once, passing the rest of the hollandaise at the table. The casserole is best served warm.
Recipe copyright 2018, Joanna Gaines, adapted from Magnolia Table (HarperCollins Publishers, 2018)