In a medium saucepan over low heat, gently combine the whole milk and heavy cream. Stir occasionally and warm the mixture, ensuring it does not reach a boil.
In a separate mixing bowl, vigorously whisk together the eggs and granulated sugar until the mixture turns pale and fluffy, resembling a light custard.
Slowly incorporate the warm milk and cream mixture into the egg mixture. Whisk continuously to temper the eggs, preventing them from scrambling and ensuring a smooth consistency.
Return the tempered egg mixture to the saucepan. Cook over low heat, stirring constantly with a wooden spoon, until the mixture thickens slightly (about 5-8 minutes). It should coat the back of a spoon, leaving a clear trail when you run your finger through it.
Once thickened, remove the saucepan from heat and stir in the vanilla bean paste, ground nutmeg, and ground cinnamon, allowing the warm, aromatic flavors to meld together. Let the mixture cool to room temperature.
Once cooled, pour the eggnog into a pitcher. Cover and refrigerate for at least 2 hours to chill and develop the flavors further.
When ready to serve, pour the chilled eggnog into frosty glasses. Top each serving with a generous dollop of whipped cream and a delicate sprinkle of ground nutmeg or cinnamon for an inviting garnish.
Notes
For an elegant display, serve the eggnog in festive glass mugs and add a cinnamon stick stirrer for an extra special touch!