Need to feed a crowd? This recipe makes 72 mini tree cookies complete with a pecan tree trunk.
In a large mixing bowl beat butter with an electric mixer on medium to high speed for 30 seconds. Add the sugar, baking powder, and salt. Beat until combined, scraping sides of bowl occasionally. Beat in egg and mint extract until combined. Beat in as much of the flour as you can with the mixer. Stir in any remaining flour. Divide dough in half. Stir melted chocolate into one half of the dough. Knead the green food coloring into the remaining half of the dough. If necessary, cover and chill dough about 1 hour or until easy to handle.
Divide the green dough in half. Shape each dough half into a 10-inch log. Flatten the sides of the logs so they have three flat sides and are triangular. Wrap each triangular log in plastic wrap. Chill about 1 hour or until firm.
Divide the chocolate dough in half. Between two sheets of waxed paper, roll half of dough into a 10x4-inch rectangle. Remove top sheet of waxed paper. Place one chilled green log in the center of the chocolate rectangle. Using the waxed paper, bring the sides of the chocolate rectangle up over the green log to enclose; press sides to seal. Repeat with the remaining chocolate dough and green log. Wrap logs in plastic wrap and freeze at least 1 hour or overnight.
Preheat oven to 375°F. Line a cookie sheet with parchment paper. Using a sharp knife, cut logs into 1/4-inch-thick slices. If necessary, rotate log every few slices to keep its triangular shape. Place slices 2 inches apart on the prepared cookie sheet. Press a pecan half into the bottom edge of each triangle slice as a tree trunk. Bake for 6 to 8 minutes or until tops are set. Transfer to a wire rack and let cool. Place cookies in bag; close bag.
Layer cookies between sheets of waxed paper in an airtight container; cover. Store at room temperature for up to 3 days or freeze for up to 3 months.