Spray an 8 inch square baking dish with non stick spray. Cut each English muffin in half and lightly toast. Then cut each half into 6 pieces. Place 1/2 of the English muffins on the bottom of the baking dish.
Sprinkle on 1/2 the Canadian bacon and 1/2 the cheese
Next, layer on the remaining English muffins, the remaining Canadian bacon and remaining cheese.
Beat eggs and milk together, seasoning with salt and pepper to taste.
Pour egg mixture evenly over casserole. Cover with plastic wrap and refrigerate at least 1 hour or up to overnight.