1 Candy Thermometer or other high-temperature thermometer (needs to go up to 250°F)
1 Stand Mixer with Whisk Attachment
1 Small (1 1/2-2qt) sauce pan
1 9×9" square non-metal baking pan*
Ingredients
4packetsunflavored gelatin (about 3T + 1 tsp)
2/3ccold water
1/4cDutch cocoa powder
1/2tspespresso powder(optional)
2tspvanilla extract
1/4cboiling water
2c+ 2T granulated sugar
2/3clight corn syrup
1/2tspkosher salt
2/3cwater
1/3cDutch cocoa powder
1/3cpowdered sugar
Instructions
Grease a 9×9" square non-metal baking dish (I like to use baking spray, but a small amount of neutral oil will work great). Set aside.
Add the gelatin and 2/3c cold water to the bowl of a stand mixer fitted with the whisk attachment. Let stand at least 5 minutes.
4 packets unflavored gelatin, 2/3 c cold water
In a small bowl, whisk together the cocoa powder, boiling water, espresso powder, and vanilla extract until well combined and glossy.
1/4 c Dutch cocoa powder, 1/2 tsp espresso powder, 2 tsp vanilla extract, 1/4 c boiling water
In a 1 1/2-2 qt saucepan, stir together granulated sugar, corn syrup, salt, and 2/3 c water. Heat over medium heat, stirring until sugar dissolves. Then raise to medium-high heat and continue cooking, without stirring, until it reaches 250°F on a candy thermometer.
2 c + 2T granulated sugar, 2/3 c light corn syrup, 1/2 tsp kosher salt, 2/3 c water
Meanwhile, add the cocoa mixture to the gelatin mixture, mixing at low speed until combined.
Once the sugar syrup comes up to temperature, slowly pour it into the chocolate-gelatin mixture, beating at low speed until all the syrup is added. Raise the mixer speed to high and beat until thick and fluffy (about 10-15 minutes). You'll know it's ready when it starts to pull away from the sides of the bowl.
Pour into your prepared pan, using a spatula to scrape the bowl well and smooth out the top of the marshmallows.
In a small bowl, sift together the 1/3 c cocoa powder and 1/3 c powdered sugar, then stir it until it's fully combined. Then use your sifter to dust the top of the marshmallows. Cover lightly with aluminum foil and let sit at room temperature overnight (or about 8 hours).
1/3 c Dutch cocoa powder, 1/3 c powdered sugar
The next morning, turn the marshmallows out of the pan onto a cutting board. If the edges of your pan are rounded, and you want straight sides on your marshmallows, cut the edges off of the marshmallow slab first (a snack for the chef!).Then cut evenly into 16 marshmallows (or more if you want smaller 'mallows). Tip: lightly grease the knife with some neutral oil beforehand and in between cuts to keep it from sticking too much.Toss marshmallows in the cocoa powder-powdered sugar mixture.
Store marshmallows in an airtight container at room temperature. Stored like this, the marshmallows can last for at least 3 weeks (although I've actually eaten them 6 weeks later and they're still great!).
Notes
*This size pan will make thick marshmallows; for thinner or smaller marshmallows, use a 9×13 pan.**I used Morton’s Kosher salt. If you’re using Diamond Crystal you’ll need to adjust accordingly (check out this article for more info).