Step 1

Coat a 9-inch by 13-inch baking dish with nonstick spray. Spread butter on one side of each bread slice and lay half (about 6 slices) face up in prepared baking dish.

Step 2

Top with Swiss cheese, ham slices, and cheddar cheese. Sprinkle with parsley, dill, mustard, 1/2 teaspoon salt, and 1/4 teaspoon pepper. Top with a second layer of bread, butter-side up.

Step 3

Combine milk and eggs in a blender and process for 30 seconds (or whisk vigorously in a large bowl by hand). Pour evenly over the top of casserole. Cover with foil and refrigerate at least 8 hours or overnight.

Step 4

Preheat oven to 275 degrees. Bake covered casserole for 30 minutes. While the casserole is baking, combine corn flakes and butter and mix well to combine.

Step 5

Remove casserole from oven. Increase oven temperature to 350 degrees. Remove foil and spread topping. Return to oven and bake, uncovered, for 45 minutes. Let stand 15 minutes before serving.