Start by combining the rye flour, teff/buckwheat flour, baking powder and salt in a large bowl.
In a food processor or hand-chopper or separate bowl, mix butter, tahini, sugar and pitted dates for a few minutes on high speed until properly combined.
At this point, add your spices or other flavorings. I added the grated ginger and crushed black pepper, but see notes below for other options.
Add the eggs to the processor and mix until combined.
Now, add the flour mix to the food processor, one cup at a time and mix completely. You don't want to overmix this.
Pour the mixture into a bowl, add the chopped chocolate and walnuts and mix to combine.
Refrigerate for 2 hours until firm or freeze for 20 minutes.
Preheat oven to 380 degrees F and line two baking trays with parchment paper.
While the oven is pre-heating, use a tablespoon measure to make small-ish balls and coat them in sesame seeds. Then place them on the baking trays an inch apart.
Bake for about 7 minutes, then remove the trays and bang/smack them down on your kitchen counter a couple times to let them flatten and crack.
Put the trays back into the oven for another 6-8 minutes until they get slightly golden/browned.
Remove from the oven and cool the cookies on the baking tray for about 10 minutes before transferring to a wire rack to cool completely.
Seal in an airtight container for up to 5 days, and enjoy!