Method

1. Preheat the oven to 350F. Line a cookie sheet with parchment or a nonstick pad and set aside.
2. Melt butter in the microwave or on the stove top and set aside to cool slightly.
3. In a large mixing bowl, whisk together the almond flour, coconut flour, salt and sweetener.
4. Add the egg whites and butter (which should be cool enough that you can hold your fingertip in it for 5-10 seconds without flinching) and stir until evenly combined. It should be slightly sticky.
5. Gather the batter into a ball and turn it out onto a cutting board.
6. Let it rest on the cutting board for 5 minutes, which will allow the coconut flour to absorb the moisture completely.
7. Once the excess moisture has absorbed, divide the dough into two equal portions. Gather the first half into a tight ball, then roll or press into a disk (about 1/2" thick).
8. Cut the disk in half, then cut each half into thirds so that you get six triangles out of the disk.
9. Transfer the triangles to the prepared cookie sheet, spacing them about 1" apart, then repeat the process with the remaining dough, to create another 6 cookies.
10. Gently poke each cookie a few times with a fork, or make a decorative border with the tines.
11. Bake for 18-20 minutes, remove from the oven and transfer cookies to a wire rack to cool completely and firm up.
12. Prepare the dipping chocolate by melting the chocolate and coconut oil in the microwave or over a double boiler. Add the espresso powder and salt (if using), and stir until completely smooth.
13. Grip each cooled cookie by the pointy end and swipe the wide end through the chocolate. Shake gently to remove excess chocolate, then transfer to a piece of wax or parchment paper to solidify.