1. Preheat the oven to 375 degrees F. Line two baking sheets with parchment paper. Crush the fennel seeds to a powder in a mortar and pestle or clean coffee grinder.
2. Fill a medium saucepan one-quarter full with water and bring to a simmer over medium-high heat. In a large heatproof bowl, combine the fennel, 7 ounces (200 g) of the chocolate, butter, and almond butter, and place over the simmering water. Stir until the chocolate is nearly all melted, then remove from the heat. The residual heat will continue melting the chocolate.
3. In the bowl of a stand mixer fitted with the whisk attachment, combine the eggs, brown sugar, and vanilla and beat on high speed until the eggs are pale and very thick, about 5 min-utes. Pour in the melted chocolate and beat on medium speed until thick, about 1 minute.
4. In a small bowl, stir together the buckwheat flour, cocoa powder, baking soda, and salt. Fold this into the batter using a spatula. Scoop 1½-tablespoon mounds of dough onto each baking sheet, leaving 2 inches of space between. Lightly press small pieces of the remaining 1 ounce (25 g) chocolate into the top of each cookie.
5. Bake for 8 to 9 minutes, until the edges of the cookies are crispy but the centers are soft. Be careful not to overbake. They might look a little underdone, but they will set while cooling. Cool on the pan for 10 minutes, or until you are able to pick the cookies up without them falling apart. They will keep for 3 days in an airtight container.
©2021 by Aran Goyoaga. Excerpted from Cannelle et Vanille Bakes Simple: A New Way to Bake Gluten-Free by permission of Sasquatch Books.