1. Take a large bowl and beat the eggs and sugar together until smooth and well combined using a hand mixer or food processor.
2. Meanwhile, take a small saucepan and heat the milk over medium heat until it starts to simmer, just don’t let it boil. Then gradually add a small amount of the hot milk to the egg mixture from step one while you’re whisking constantly – this is also known as tempering and prevents the eggs from cooking too quickly and curdling to scrambled eggs. 
3. Once done, slowly pour the tempered egg mixture back into the saucepan with the remaining milk and add the heavy cream, cinnamon, nutmeg, and vanilla extract while you’re still whisking constantly – then cook it over low heat while you continue to stir it constantly.
4. Once your eggnog mixture is thick enough to coat the back of your spoon (takes about 5-7 minutes) remove it from the heat and stir in the brewed coffee or espresso – mix everything well.

Finally, I love it hot, but if you like it cold, pour it into a pitcher or other big container, let it settle and cool off at room temperature, and then chill it in the fridge for at least 2 hours.

Pour a shot of espresso into your favorite glasses or cups and top it off with the eggnog mix,  whipped cream and maybe chocolate or crushed cinnamon – enjoy this classic holiday drink!.