Preheat the oven to 350°F. Line an 8x8–inch pan with parchment paper.

Place the butter and sifted cocoa powder in the top of a double boiler and cook over medium heat to melt the butter. Add the chopped chocolate to the melted butter and stir until the butter and chocolate have melted and combined. Set the double boiler on a wire rack and let the chocolate mixture cool while you prep the other ingredients.

In the bowl of a stand mixer fitted with the whisk attachment (or a large mixing bowl and a hand mixer), combine the eggs, sugars, and vanilla. Whisk on low until combined, for 1 to 2 minutes. Use a spatula to scrape down the bottom and sides of the bowl as necessary.

Increase the mixer to medium and slowly pour in the chocolate mixture, aiming for the sides of the bowl so the whisk doesn’t spit batter back at you. Continue whisking on medium until the batter is smooth, about 1 minute.

In a small bowl, combine the buckwheat flour, sweet rice flour, tapioca starch, and salt. Add the dry ingredients to the batter and use a spatula to mix until just combined.

Pour the batter into the prepared pan and smooth the top. Bake for 30 to 35 minutes, or until a skewer inserted into the center comes out with a few crumbs attached.

Do not overbake; take them out when they still seem underbaked. Once they cool they will firm up. Cool completely on a wire rack before slicing. When the brownies are completely cooled, they can be stored in an airtight container at room temperature for up to 3 days.

VARIATIONS

Add raspberry jam to the batter and swirl it around just before placing in the oven. Add peanut butter to the batter and swirl it around just before placing in the oven. Add candied walnuts to the batter before putting it in the pan.

Make s’mores brownies by making a gluten-free graham cracker crust, then pour the brownie batter on top and bake. After the brownies are cool, make meringue frosting and spread on top.