1Blend confectioners' sugar and cocoa in a microwaveable medium bowl. Pour in milk. Place butter on top. Heat in microwave oven at full power for 2 minutes or until butter melts. Stir well to mix. Add vanilla and pecans. Stir until blended. Put in refrigerator and chill 1 hour until firm. Cut into 1-inch squares. Store in airtight container.