Set (6 quart) instant pot to sauté on low heat. Fill instant pot with 5 cups of water, bring to a boil. If you have a glass lid for your instant pot, this would be a great time to use it. It will help the water come to a boil much faster.
Add eggs to a deep Pyrex bowl (1.75q) and whisk well. The bowl should be heat safe and fit comfortable into your instant pot.
Add heavy cream, vanilla extract, ground cinnamon, light brown sugar, milk, granulated sugar and nutmeg to the bowl and whisk to blend.
Using a trivet, lower the bowl into the instant pot. Water should come up about ½ way on the sides of the bowl. If the water level has decreased or does not reach the halfway mark on the bowl, add more hot water.
Add cinnamon stick and star anise to the eggnog and whisk every 30 seconds until mixture starts to boil. Once it just barely starts to boil move to the next step.
Switch settings on instant pot to “keep warm." Once eggnog reaches 160F degrees. Remove from heat.
Discard cinnamon stick and star anise. Let cool overnight in the fridge or for at least 2 hours before serving. This can also be served warm if you prefer.
Notes
The benefit of using the instant pot is you get a consistent temperature for the entire process. This can also be done on the stovetop using a double boiler. The key to making it on the stovetop is to keep a close eye on the temperature so it doesn't get too hot, too quickly. Gentle, even heating is the key with eggnog.
This eggnog can be spiked for the adults who want a little something extra. For every cup (8 ounces) of egg nog, you'll want about an ounce of alcohol. My favorites to add to egg nog are spiced rum, bourbon, whiskey or Bailey's Irish cream.
Star anise has a flavor that is similar to licorice but not overpowering. If you don't like that flavor, just leave it out. Some other options include: pumpkin pie spice, apple pie spice, or cloves.
Store the finished egg nog in the refrigerator. It will keep for about 10 days. I usually give it a good stir before serving.
In preparing this, you'll want to use a deep (not wide) bowl that is oven (heat) safe. I am using a Pyrex-brand bowl for this recipe. You'll want to test to make sure the bowl you are using will fit comfortably inside your electric pressure cooker.