In a food processor, add buckwheat and walnuts and process until a semi-fine meal is formed. It's okay if some of the buckwheat groats are still whole.
Then, add in cacao, agave, and dates and process until a sticky dough is formed.
In a small pan lined with parchment paper (I used a bread loaf pan), press crust down evenly.
Chocolate Ganache
In a bowl, combine melted coconut butter, agave, and cacao powder and mix until evenly combed. Pour over crust layer into the pan. Set into freezer while you make the chocolate topping.
Chocolate Topping
In a bowl, combine melted coconut oil, cacao powder, and agave and mix until evenly combined. Pour over chocolate ganache layer and set in the freezer to harden.
Putting It All Together
Let brownie bars set in the freezer for an hour. When finished setting, cut into slices and serve.
Brownie bars will keep in the refrigerator for up to a week.