Step 1

Line an 8x8" (or larger 9x9") pan with 2 sheets of unbleached parchment paper going perpendicular to each other. This is so you can easily lift up the marshmallows when they are set.

Step 2

If using, sprinkle 1 to 2 tablespoons of the optional dusting cacao powder over the parchment paper. Set aside pan.

Step 3

Assemble stand mixer with mixing bowl and whisk attachment, or use a large mixing bowl with hand-held mixer.

Step 4

Add 1/2 cup filtered water to mixing bowl. Sprinkle gelatin over the water.

Step 5

While gelatin is blooming, combine remaining filtered water, honey, and sea salt in a medium-sized sauce pan with high edges.

Step 6

Bring to a boil over medium high heat. If you have a candy thermometer, place it in the honey mixture.

Step 7

Stir constantly to keep the mixture from bubbling and foaming over. Simmer until the temperature reaches 240 degrees Fahrenheit (about 8 to 9 minutes if you don't have a candy thermometer).

Step 8

Remove honey mixture from heat. Add the vanilla extract.

Step 9

Whisk sifted cocoa powder into the hot honey mixture until fully combined.

Step 10

With the mixer on low, SLOWLY and carefully drizzle the hot honey-cacao mixture in a thin continuous stream down the side of the bowl. To give you an idea of how slowly you need to pour, this step should take you about 1 minute.

Step 11

Beat on high for about 15 minutes -- until the mixture becomes thick and glossy with soft peaks. The marshmallow fluff will increase in volume.

Step 12

Turn off the mixer and transfer the chocolate marshmallow fluff to the lined pan. Use a spatula to smooth the top.

Step 13

Let the chocolate marshmallows set at room temperature for at least 8 hours or, ideally, overnight.

Step 14

When set, remove the marshmallows by lifting the parchment paper flaps. Place on a flat surface or large cutting board, with the marshmallows still on the parchment paper.

Step 15

Carefully peel the parchment paper away from the sides of the marshmallows. It should release easily if you do it slowly.

Step 16

If using, sprinkle the remaining optional dusting cacao powder over the marshmallows.

Step 17

Use a large chef's knife to cut the marshmallows into desired size and shape. Dust knife with cacao powder if necessary. For cutting ideas, see below.