If you want to flavour things (cakes, cookies, frostings, etc) to be “eggnog”, DO NOT just add eggnog from a carton.
1) Store-bought eggnog is garbage. Stop drinking it. It’s easy to make and you will not be disappointed, except for in yourself for having never made eggnog before.
2) The flavour of eggnog comes from the base, which is egg yolks cooked with milk and sugar. Eggnog is just base diluted with cream*. Flavour your baking with the base, not the diluted drink.
To make the base, whisk 1 yolk with about 1/4 cup of milk, 1 tbsp of sugar, and whatever spices you like (nutmeg is common, but I like vanilla and cardamom) over medium heat. Whisk constantly until it thickens and bubbles slightly. Make as much base as you need.
This PSA was brought to you by watching a bunch of stupid people on youtube add store-bought eggnog to things that should otherwise taste good.
*when I make my eggnog, I don’t use the recommended half-and-half, and opt for whole milk instead. Still 1000X better than the crap in the carton.