These Hot Chocolate Truffles and Peppermint Swirl Marshmallows have extra-large deliciousness melted with milk to produce a rich, creamy mug of hot chocolate. I mean all you have to do is look at this and you'll immediately want it!
Line a 9x13-inch baking pan with aluminum foil or plastic wrap, and spray the foil or plastic wrap with nonstick cooking spray.
Place the room temperature egg whites in the bowl of a large stand mixer fitted with a whisk attachment.
Pour 1/2 cup of the cold water in a small bowl, and whisk in the gelatin. Set the bowl aside to let the gelatin "bloom," or absorb the water.
Pour the remaining 1/2 cup of water in a medium heavy-bottomed saucepan, and stir in the granulated sugar, the light corn syrup, and the salt. Place the pan over medium-high heat and continue to stir until the sugar dissolves. Brush down the sides of the pan with a wet pastry brush to remove any stray sugar crystals. Insert a candy thermometer.
Cook the sugar syrup, without stirring, until the thermometer reaches 260° Fahrenheit. This will take 10-15 minutes, so while you're waiting for the sugar to cook, microwave the gelatin bowl for about 20 seconds, until the gelatin liquefies.
When the sugar syrup reaches 245° Fahrenheit, begin beating the egg whites on medium speed. The egg whites should be well-beaten and be able to hold firm peaks at approximately the same time the sugar syrup reaches 260° Fahrenheit.
When the sugar syrup is at 260°, remove the pan from the heat and carefully whisk in the liquid gelatin mixture. It will bubble up and steam a bit, so watch your hands during this step.
The hot sugar syrup now needs to be added to the egg whites. If your saucepan does not have a spout, pour the syrup into a large mixing cup or pitcher with a spout, to give you more control over the process. Turn the mixer to low, and with the mixer running, slowly stream the hot sugar syrup into the beaten egg whites. Try to pour the syrup close to the sides of the bowl, so it doesn't hit the whisk and splatter everywhere.
Once all of the syrup is added to the whites, gradually increase the speed of the mixer until it is running on medium-high speed. Whip the marshmallow until it is very thick, shiny, and opaque, about 8-10 minutes depending on your mixer. When you lift the whisk from the marshmallow, it should slowly stream from the whisk in a thick ribbon. Add 1/2 teaspoon of peppermint extract and mix for 20 seconds to incorporate it. Taste the marshmallow, and if you would like a stronger mint flavor, mix in an additional 1/2 teaspoon of peppermint extract.
Pour the marshmallow into the prepared pan and smooth it into an even layer. Drizzle red food coloring over the top of the marshmallow in a random pattern. Drag a toothpick through the marshmallow, swirling the food coloring on top. Stop before the colors start to bleed, while you still have distinct red and white swirls. Let the marshmallow sit and rest, undisturbed, at room temperature until it is completely set, about 8 hours.
When you're ready to cut the marshmallow, dust your work surface with powdered sugar, and sprinkle a layer of powdered sugar on top of the marshmallow. Flip the marshmallow face-down on the work surface and peel the foil or cling wrap off the back. Dust a large chef's knife with powdered sugar and cut the marshmallow into long thin strips, cleaning the knife frequently as it gets sticky. Cut the strips of marshmallow into small squares. Toss the marshmallows squares in powdered sugar to prevent them from sticking together. Store the marshmallows in an airtight container at room temperature for up to two weeks.
Do not attempt to make marshmallows when it is stormy or humid—they will absorb moisture from the air and will be unpleasantly sticky and gummy.