In a medium saucepan, combine the whole milk and heavy cream. Set the heat to medium and stir the mixture frequently as it warms. Heat until the mixture is steaming, ensuring it does not come to a boil.
While the milk mixture is heating, crack the egg yolks into a separate mixing bowl. Add the granulated sugar to the bowl and whisk vigorously until the egg yolks become pale in color and the mixture achieves a creamy texture.
To temper the egg yolks and prevent them from cooking too quickly, carefully pour about 1 cup of the warm milk and cream mixture into the beaten egg yolks. Whisk continuously as you add the milk to ensure an even temperature throughout.
Once the egg mixture is well combined, pour it back into the saucepan with the remaining warm milk and cream. Stir the mixture over medium heat, allowing it to thicken slightly which should take about 5-7 minutes.
After thickening, remove the saucepan from heat and stir in the vanilla extract, ground cinnamon, ground nutmeg, cayenne pepper, and maple syrup. Mix until all ingredients are fully integrated and the flavors are well combined.
Carefully transfer the eggnog into a bowl or pitcher. Allow it to cool to room temperature before placing it in the refrigerator. Chill for at least 2 hours, or overnight for best results.
To serve, pour the chilled eggnog into glasses. Top generously with whipped cream and garnish each serving with a cinnamon stick for a festive and aromatic touch.
Notes
Adjust the cayenne pepper to taste for desired spiciness.