Mix coconut flour, tapioca flour, sweetener, matcha powder and salt together in a bowl.
Add in room temperature butter and mix until butter is fully incorporated into the dry ingredients. It's best to use your hands here, because you don't want any clumps of butter left. Once it is well-mixed, you should be left with a dough with a playdough-like consistency.
Roll into a log approximately 1.5 inches in diameter. Cover in plastic wrap and place in the fridge until hardened, approximately 30 minutes to 1 hour.
Remove log from the fridge, and preheat oven to 350F.
Slice log into 1/4 inch thick rounds, and place onto a lined baking sheet. The cookies will not expand much, so you can place them fairly close together, but not touching.
Bake for 12-14 minutes, or until edges begin to brown.
Nutrition Facts (per cookie, recipe makes 8 cookies): 85 calories, 8 g total fat, 9 g total carbs, 2 g fiber, 5 g carbs from sweetener from Pyure stevia blend (2 g net carbs), 1 g protein