Step 1

In a large measuring cup or bowl, whisk together egg nog, eggs, brown sugar, cinnamon, nutmeg, and rum (if using).

Step 2

Spray a 9-by-13-inch glass baking dish with cooking spray. Add the bread cubes into the pan. It will be a tight fit but that's ok. Press them down gently, if need be.

Step 3

Gently pour the eggnog mixture all over the bread cubes. Using the back of a spatula, press down on the bread cubes to help the bread soak up the liquid a bit. The bread will continue to soak up the liquid overnight.

Step 4

Top the dish with chopped walnuts and cover tightly with foil. Place in the refrigerator to chill overnight.

Step 5

When ready to bake, preheat oven to 350 °F (177 °C)

Step 6

Unwrap the dish (save the foil) and bake uncovered for 30 minutes. The top will be nice and golden brown.

Step 7

After 30 minutes, cover the dish with the foil you saved and bake for another 15-20 minutes, just to make sure the center is set and everything is warmed through.

Step 8

Remove from oven and serve hot with maple syrup.