Beat butter in a medium mixing bowl with an electric mixer on medium to high speed for 30 seconds. Add the brown sugar, espresso powder, cocoa powder, and dash salt. Beat until combined, scraping sides of bowl occasionally. Beat in egg yolk and coffee liqueur until combined. Beat in as much flour as you can with the mixer. Stir in remaining flour with a wooden spoon.

Divide dough in half. If necessary, cover and chill until dough is easy to handle.

Heat oven to 350 degrees F. Roll one dough portion at a time on a lightly floured surface until 1/4-inch thick. Cut out dough with desired 2-1/2- to 3-inch cookie cutters. Place cutouts 1 inch apart on an ungreased cookie sheet.

Bake about 12 minutes or until bottoms are lightly browned. Cool on cookie sheet for 1 minute. Transfer cookies to wire racks and cool completely.

Combine chocolate pieces and shortening in a heavy small saucepan; stir over medium-low heat until melted. Dip a part of each cookie in chocolate mixture. Makes 18 to 24.

Place in layers separated by waxed paper in an airtight container; cover. Store at room temperature up to 1 week or freeze undipped cookies up to 3 months; thaw, then dip.