Preheat your oven to 350°F (175°C) and grease a 9x13 inch baking dish.

In a large mixing bowl, combine eggnog, eggs, whole milk, sugar, vanilla, cinnamon, nutmeg, and salt, whisking until smooth.

Add the bite-sized pieces of donuts into the custard mixture, gently stirring until each piece is coated. Fold in raisins or cranberries if desired.

Let the mixture rest for about 10-15 minutes to allow donuts to absorb the custard.

Pour the mixture into the prepared baking dish, spreading it evenly.

Bake for 40-50 minutes or until golden-brown on top and the center is set.

Remove from the oven and allow to cool for about 10 minutes before serving.

Serve warm topped with whipped cream and a sprinkle of cinnamon or nutmeg.