a 12-cup Bundt pan, a skewer, a piping bag fitted with a long thin round tip, a candy thermometer and a small offset spatula
- For the cake and filling: Coat a 12-cup Bundt pan with cooking spray. Prepare and bake the devil’s food cake according to the package directions. Let cool completely.
- Combine the butter and marshmallow creme in a large bowl and beat with an electric mixer until smooth and well combined. Add the confectioners’ sugar and heavy cream and beat until fluffy, about 3 minutes. Transfer the marshmallow mixture to a piping bag fitted with a long thin round tip.
- Flip the cake so it is flat-side up. Make 12 evenly-spaced holes in the bottom of the cake using a skewer, pressing only halfway down into the cake and wiggling the skewer slightly to widen the holes until they are each about 1 inch wide. Insert the piping tip in each of the holes and pipe in some marshmallow mixture until it starts to ooze out the top of the hole. Flip the cake flat-side down onto a cake stand or serving platter.
- For the topping: Combine the coconut and confectioners’ sugar in a large resealable plastic bag, seal and shake well. Dissolve 5 to 6 drops of food coloring in 2 tablespoons water in a small bowl. Drizzle the food coloring over the coconut and toss well, massaging the bag with your hands to evenly distribute the color.
- Combine the gelatin with 6 tablespoons water in a small bowl and set aside. Combine the granulated sugar, corn syrup, salt and 1/4 cup water in a medium saucepan and cook over medium heat until it reaches 235 to 240 degrees F (soft-ball stage) on a candy thermometer, 5 to 6 minutes. Remove from the heat.
- Pour the corn syrup mixture into the bowl of a stand mixer fitted with the whisk attachment, along with the vanilla and bloomed gelatin. Whip on high speed until thick and fluffy, about 6 minutes.
- Spread the marshmallow mixture all over the cake with a small offset spatula. Pat the coconut all over the cake. Let sit 30 minutes for the topping to set before serving.