First, come the marshmallows. Yes, you are going to MAKE MARSHMALLOWS (thanks, Alton Brown).
This is what you need
3 packages plain unflavored gelatin
1c very cold water
12oz sugar- this is about 1.5c, but I did weigh it out
1c light corn syrup
1/4c powdered sugar
This is what to do with it
Get a pretty big bowl, which you're going to use to mix this all up. If you have a stand mixer, more power to you, this is going to be a lot easier- I did it with a hand mixer. Put the gelatin in the bowl along with 1/2c of the cold water.
You should also take a minute to prep the pan you'll use- I used a jelly roll pan, but they turned out kind of flat, you can also use a 9x13. Combine the powdered sugar and cornstarch. Then, spray the pan, and coat the pan with the mixture.
Now, in a sauce pan put the rest of the water, the corn syrup, the regular (granulated) sugar, and the salt. You are going to need a candy thermometer. SLOWLY bring it up to 240 and then immediately remove from heat. I have learned from years of fudge making experience that slow is key for a smooth final product.
Next you will slowly pour the corn syrup mixture into the gelatin, and start to mix. I recommend setting up some kind of music listening or movie watching situation for yourself because this is going to take a while.
You are going to keep whipping it until it gets thick. This will take something in the neighborhood of 15 solid minutes of whipping. If you have a hand mixer lets just hope you do weight training.
Eventually it will get very stiff- when this is happening, throw in the vanilla and keep going for a few more minutes. It is actually kind of amazing how it transforms, but at this point your arm will be tired and you'll just be glad something happened. Pour it into your prepped pan and spread around evenly.
As you can see from the pictures, it was already dark when I did this, so I let mine sit overnight- you can also let it sit for 3-4 hours. You will be dying to know if it worked- just resist too much poking and prodding because you'll make your mallows look gross.
When its cold, you'll see that it has formed some kind of strange flexible marshmallow sheet.
Get a surface ready that is substantially larger than your pan- coat it with the rest of the cornstarch/sugar mixture. Now, you can cut the marshmallow with a pizza wheel (which is actually kind of fun).
At this point obviously you can eat them just like they are- in hot chocolate and s'mores and whatnot.
You will notice that they really truly do taste like marshmallows. This means two things:
1. hurray! you have successfully replicated marshmallows!
2. you have just spent 2 days making something that tastes exactly like a product available for $2 at the grocery store. (but square! these are square! that makes them totally different, right?)
At any rate, do what you will. I decided to make them into a fancy dessert. For this, you need:
1 bag semisweet chocolate chips
1 package of candy canes- crushed in the food processor (or with a hammer, if your arm has recovered)
I recommend covering every available surface with wax paper right about now (especially if you just cleaned up the drifts of powdered sugar)
Put the chips in a microwave safe container. In SMALL increments, melt them. Be aware that microwaved chocolate won't necessarily look melted- sometimes it holds shape despite being melted inside. Always try a stir test before going back in. If you overcook, it will be ruined.
Now set up a little assembly line- dip in the chocolate, then the minty chips, then set on the wax paper to set.
You will become acutely aware of how very many marshmallows that recipe makes by the end.
Let them set, and then enjoy! The marshmallows will keep for 3-4 days in a closed container, and I think these last about that long as well. Some of them will be prettier than others, but they are tasty and definitely look impressive if you want something for a Christmas party.
Good luck, and Merry Merry Christmas!