Preheat the oven to 350°F (175°C) and grease a 9x13-inch baking dish.
In a large bowl, combine the torn English muffins and chopped Canadian bacon. Spread the mixture evenly in the prepared baking dish.
In another bowl, whisk together the eggs, milk, Dijon mustard, salt, and black pepper until well combined.
Pour the egg mixture over the English muffin and bacon mixture in the baking dish. Gently press down to ensure the muffins soak up the egg mixture.
Sprinkle the shredded cheddar cheese and chopped chives over the top.
Cover the dish with aluminum foil and bake for 30 minutes.
Remove the foil and bake for an additional 15-20 minutes, or until the casserole is set and lightly golden on top.
Allow to cool for 5 minutes before serving. Drizzle with hollandaise sauce before serving.