Lightly toast the English muffin halves, cut them into chunks, and arrange half in a greased 9x13 baking dish along with half the Canadian bacon.
Repeat the layering process with the remaining muffins and bacon.
In a large mixing bowl, whisk together the eggs, milk, cream, salt, pepper, and Dijon mustard until smooth.
Pour the egg mixture evenly over the layered muffins and bacon, making sure everything is coated.
Cover the dish with foil and refrigerate overnight to allow the flavors to meld.
The next morning, preheat the oven to 375°F (190°C), uncover the casserole, and bake for 40–45 minutes until set and golden.
While it bakes, prepare your hollandaise sauce (store-bought mix or homemade).
Once baked, drizzle the warm hollandaise generously over the casserole before serving.