Yes you need egg yolks to make eggnog. In my opinion this is so easy to make that I think more people should be making their own eggnog instead of buying it. The Holidays can make everyone a little crazy, but it's easier to relax when you're sitting with a nice chilled glass of homemade eggnog.
3 cups (710ml) whole milk
1/2 vanilla bean or 1.5 teaspoon (6g) vanilla extract
6 egg yolks
1 cup (220g) granulated sugar
1tsp (3g) cinnamon
Heaping 1/4 tsp (1g) cloves
1tbsp plus 2tsp (7g) ginger powder
1.5tsp (4g) ground nutmeg *ideally fresh ground*
1/4cup cup (60ml) rum, brandy, or cognac *optional but recommended*
1.5 cups (354ml) heavy cream
Bring milk to a simmer. While the milk is simmering, have the egg yolks and sugar ready in a separate bowl and using an electric mixer, whip them until they are light in color.
Once the milk has simmered, slowly temper the milk into the egg yolk mixture by gradually scooping in a little at a time until milk has fully combined with the egg yolk mixture. Think about the process of making pastry cream, they are practically identical.
Add vanilla bean.
Consistently stir for 10-15 minutes using a spatula in low heat to prevent curdling. Do not boil. Look for a nappe consistency (coats the back of a spoon when you run your finger through it.
Strain through a fine mesh sieve in a metal bowl.
Place on ice water bath.
Add cinnamon, clove, ginger powder, nutmeg, rum/brandy, and heavy cream.
Store and serve as needed.
To finish, add extra whipped egg whites, alcohol, or more nutmeg as desired in a glass.