1/2 cup (70 g) all purpose gluten free flour (I used Better Batter)
1/4 teaspoon xanthan gum (omit if your blend already contains it)
5 tablespoons (25 g) unsweetened natural cocoa powder
1 tablespoon (9 g) cornstarch
1/4 teaspoon kosher salt
4 eggs (200 g, weighed out of shell) at room temperature, separated into yolks and whites
3/4 cup (150 g) granulated sugar
6 tablespoons (84 g) unsalted butter, melted and cooled
1 tablespoon warm water
Confectioners’ sugar, for rolling
Marshmallow creme (homemade or store-bought), for filling
14 ounces semisweet chocolate, chopped
3 tablespoons (42 g) virgin coconut oil
Preheat your oven to 350°F. Line a 13-inch x 18-inch rimmed baking sheet (a half-sheet pan) with unbleached parchment paper and set it aside.
In a medium-size bowl, place the flour, xanthan gum, cocoa powder, cornstarch and salt, and whisk to combine. Set the dry ingredients aside. In a large bowl, place the egg yolks, 1/2 cup (100 g) of the granulated sugar, the butter, and the water, and whisk vigorously until smooth and pale yellow. Add the dry ingredients to the egg yolk mixture, and whisk to combine. The mixture should be thick but smooth. Set it aside.
In the bowl of a stand mixer fitted with the whisk attachment or a large bowl with a hand mixer, place the egg whites and beat on medium-high speed until soft peaks form. Add the remaining 1/4 cup (50 g) of granulated sugar and continue to beat on medium-high speed until glossy peaks form. Add the egg white mixture to the large bowl of egg yolks in two parts. After adding the first part, whisk to combine well. After adding the second part, carefully fold in the remaining egg whites until no white streaks remain. The batter will be fluffy. Pour it into the prepared baking sheet and spread into an even layer with a spatula.
Lay a flat-weave kitchen towel (a tea towel) flat on a large, clean flat surface and sprinkle it generously with confectioners’ sugar. Place the baking sheet in the center of the preheated oven and bake for 12 to 14 minutes, or until the cake springs back when pressed gently. Remove the cake from the oven and, working quickly, immediately turn the warm cake onto the center of the prepared tea towel. Carefully remove the parchment paper from what was the underside of the cake. You now have a bare cake on a sugared tea towel. Fold the exposed ends of the tea towel over the cake and roll it tightly away from you, with the towel. Place the cake, as coiled in the towel, on a wire rack to cool completely. Once the cake has cooled, unroll it on a flat surface and spread the marshmallow creme filling on top of the cake, leaving a 1/2-inch clean border all around the cake. Reroll the cake tightly and place seam-side down, on a wire rack.
Prepare the glaze by placing the chopped chocolate and virgin coconut oil in a small, heat-safe bowl and melting either in the microwave in 30-second bursts, stirring well in between, until melted and smooth or in a double boiler. Allow the chocolate to sit at room temperature briefly until it begins to thicken a bit. Pour the glaze over the top of the cake on the wire rack. Allow the glaze to set at room temperature before slicing and serving.
Originally published on the blog in 2011 (!). Recipe as written adapted from Little Debbie-Style Swiss Rolls on page 119 of Gluten Free Classic Snacks: 100 Recipes for the Brand-Name Treats You Love.