Preheat the oven to 350ºF. Spray a 2-quart baking dish with nonstick cooking spray.

Cut the croissants into cubes and place in the baking dish.

Crack the eggs into a large bowl and lightly whisk. Add the eggnog, sugar, vanilla extract, rum extract and nutmeg and whisk to combine. Pour the egg mixture over the top of the cubed croissants. Lightly press the croissants, making sure all of the pieces are soaked in the egg mixture. Let sit for 10 minutes.

Bake the bread pudding in the preheated oven until the center is set and the top is golden brown, 30-35 minutes.

While the bread pudding is baking, make the syrup. Melt the butter in a large saucepan. (You will want to make sure you use a larger saucepan, as the mixture will bubble up when you add the eggnog, and again when you add the baking soda. I use a 3 quart saucepan.) Add the sugar and stir until the mixture turns a caramel color, 6-8 minutes. The mixture will look like it is separating - don’t be alarmed. When the mixture is golden brown, slowly whisk in the eggnog. The mixture will bubble up and may seize, but just keep whisking. Bring the mixture back up to a bubble and boil for a minute or two. Remove from the heat and whisk in the baking soda. Let the syrup cool slightly before serving.

Serve the bread pudding warm, topped with the caramel syrup.