I'm a little slow on this one, but I think you can still find Eggnog in stores for a little bit longer. Run out and buy a quart so you can make this. You'll thank me later. Unless you are on a diet. Then you will curse me. Whatever. Eat it. You're welcome.
The method for cooking this candy is exactly like chocolate fudge, so if you want a step by step with photos try this post on making chocolate fudge. The sugar measurement looks weird. I had to adjust the sugar in the recipe because eggnog has sugar in it already. Basically it's 3 c minus 2 T. Remember that sweating the pan and not scraping the pan out after cooking are the two most important steps in making sure your fudge does not sugar. Also make sure you use a clean spoon after the candy has sweat in the pot. If you stirred before sweating the pan, wash the spoon carefully to be sure no sugar is sticking to the spoon. Do not ignore these steps.
3 T butter
1 1/2 c prepared eggnog (store bought works perfectly.)
1/4 c light corn syrup
1/4 t salt
2 3/4 c + 2 T sugar
2 t vanilla
1/8-1/4 t nutmeg (to taste)
Combine all except vanilla and nutmeg in a 4 quart pot. Put a lid on the pot and cook over medium heat until the candy comes to a rolling boil. Let it boil for 2-5 minutes with the lid on. Remove lid and add candy thermometer. Cook and stir until mixture reaches exactly 238 degrees. Pour out into bowl of stand mixer; do not scrape out the pan. Just pour out the candy that comes easily and leave the rest in the pan. Let the mixture sit at room temperature until it reaches about 110 degrees. Add vanilla and nutmeg. Beat with the mixer using the flat paddle on medium speed. When mixture begins to lose it's gloss, scrape out into buttered 8x8 baking pan. Let cool until firm. Cut and serve. Makes about 2 lbs.
If you can wait a week before eating this fudge, you'll be even happier. This fudge really intensifies in flavor as it sits and "ripens." The texture smooths out and you can really taste that wonderful eggnog flavor. Have fun with this one.