Spray 9x13 baking dish with Pam. Cover bottom of pan with bread slices. Drizzle melted butter over bread. Slice cream cheese and lay on top of bread.
Cream cheese is kind of tricky-just distribute as evenly as possible. Spread shredded cheese on top. Mix eggs, milk, chilies, mustard and salt together and pour over the cheeses.Cover and refrigerate overnight. Bake (uncovered) at 350 for one hour.