Step 1

Melt butter in an 8x8 inch glass baking dish or small casserole dish. Add croutons and toss to coat. Sprinkle cheese on top of croutons. In a large bowl, beat together eggs, milk and dry mustard. Pour egg mixture over croutons and cheese. Sprinkle on cubed ham. Cover with plastic wrap, and refrigerate overnight.

Step 2

Preheat oven to 375 degrees F (190 degrees C). Let casserole stand at room temperature while oven heats.

Step 3

Bake in preheated oven for 40 minutes, until eggs are set. Let sit for 5 minutes before cutting. Can also be frozen and microwaved later.