Hazelnut-Espresso Sandwich Cookies

1
In large mixing bowl, cream butter and sugar. Beat in the egg, yolk, espresso granules and vanilla.
2
Combine flour, salt and baking powder; gradually add to creamed mixture mixing well. Stir in hazelnuts.
3
Divide dough into thirds; flatten each portion into a circle. Wrap each in plastic wrap; refrigerate for 1 hour or until easy to handle.
4
On a lightly floured surface, roll out one portion of dough to 1/8 inch thickness. Cut with a floured 1 1/2 inch cookie cutter; place 1/2 inch apart on ungreased baking sheet. Repeat with remaining dough.
5
Bake at 375* for 6-8 minutes or until edges begin to brown. Remove to wire racks to cool.
6
FOR FILLING: in small saucepan, bring cream to boil. Remove from heat; stir in milk chocolate chips and 3/4 cup semi sweet chocolate chips until melted. Transfer to a bowl and refrigerate for 1 1/2 hours or until filling reaches spreading consistency, stirring occasionally.
7
Spread filling over the bottom of half of the cookies; top with remaining cookies. Melt remaining semisweet chocolate chips; drizzle over cookies.
8
Let stand until set. Store in an airtight container in refrigerator.