• Pour milk into a medium pot and heat gently over medium heat with cinnamon and nutmeg.
  
• While the milk is warming, prepare the egg yolks: in a large bowl, whisk egg yolks and sugar together until thick and lighter in color. Once the milk is hot but not quite simmering, reduce heat to low.
  
• Temper the egg yolks by whisking about 3/4 cup hot milk into the egg yolks and sugar.
  
• Pour the tempered egg mixture into the pot with the rest of the hot milk. Cook very gently, stirring constantly, until thickened. This should take about 5 minutes.
  
• Remove from heat and stir in vanilla extract, rum extract (or chosen alcohol), half and half and heavy cream.
  
• Optional step: for a smoother eggnog, strain using a fine mesh strainer lined with cheesecloth.
  
• Pour into an airtight container and refrigerate until completely chilled. Serve with extra nutmeg.
  

For Traditional Egg Nog:

• Whip the 4 egg whites (the ones you didn't use from the egg yolks above) until stiff peaks form. Fold into chilled egg nog and serve.