Make Ahead Ham and Cheese Breakfast Casserole Recipe. Use up leftover Thanksgiving, Christmas, Easter -- whatever holiday -- ham with this DELICIOUS EASY breakfast or brunch bake. Great for a crowd of in-laws and overnight guests. It may just be the very BEST brunch of all brunch recipes EVER! You'll need bread, onion, bacon or pancetta, eggs, milk, Gruyère cheese, and a few more ingredients.