Spray an 8-inch baking dish with nonstick cooking spray. Cut the English muffins into 1-inch cubes. Place half of the cubes in the prepared baking dish, then sprinkle with half of the Canadian bacon. Top with the remaining English muffin cubes and then the remaining Canadian bacon.

Whisk together the eggs and the milk. Season with salt and pepper. Pour the egg mixture evenly over the top of the bread. Use your hands to press down the bread to make sure that it has all been soaked with the mixture. Cover and refrigerate for several hours, preferably overnight.

Preheat the oven to 350ºF. Remove the casserole from the refrigerator and let it sit on the counter while the oven comes up to temperature. Bake, uncovered, until puffed and golden and a knife inserted in the center comes out clean, 50-60 minutes.

When the casserole is almost finished baking, prepare the hollandaise sauce. Place the egg yolks, Dijon, lemon juice and hot sauce in a blender. Blend for several seconds. Very slowly, stream the hot butter into the sauce, keeping the blender on the entire time. Blend until the sauce is thick.

Serve the casserole warm with the hollandaise poured over the top.