Cream together butter and honey. Add vanilla and mint extract.
Combine flour, cocoa powder, and salt. Add walnuts. Place in plastic bag, and shape into a log about 1-1/2" in diameter. Refrigerate for 1 hour or more. Preheat oven to 350°F.
Slice refrigerated dough into 18 cookies. Place on a parchment-lined baking sheet and bake for 20 minutes, watching carefully to prevent burning. Makes about 18 cookies.