Combine the almond flour, flax, sweetener, coconut flour, gelatin, baking powder, and salt in a food processor. Pulse to combine. With the machine running slowly pour in the coconut oil, egg yolk, and almond extract. The dough will come together in a ball. Scrape down the sides of the food processor and add the 1/2 cup chopped almonds. Pulse just enough to incorporate the almonds into the batter.
On a parchment-lined baking sheet form the dough into a long rectangular log, about 4 x 10 inches. Bake for 20 minutes.
Remove the dough from the oven and cut the log into 10 pieces. Use a big knife and press down. Wiggle the knife back and forth between the pieces so that there is a gap between them. Return to the oven, reduce the heat to 225 degrees and bake for an additional 40 minutes. Cool completely.
To coat the biscotti in chocolate simply turn on the side and drizzle and spread the chocolate on the bottom. Then flip upright again to coat the top and sides. Sprinkle with the additional chopped almonds.
These are a little too fragile to dip into the melted chocolate. It works better to spread the chocolate on them. They firm up more when chilled.