These easy-to-make Hazelnut Sandwich Cookies are the perfect combination of hazelnut and chocolate. Hazelnut shortbread cookies are filled with milk chocolate ganache for a delicious cookie.
Add the flour, hazelnut flour, both sugars, cinnamon, and salt to the food processor bowl and process to combine.
Cut the butter into cubes, add to the dry ingredients and run the processor until the dough resembles bread crumbs.
Don't let the dough form into a ball of dough. It should still be somewhat crumbly and a little cold from the butter.
Place the cookie dough onto a lightly floured surface and press the dough together until it forms into a ball
Roll the cookie dough into 1/4-inch thickness. Use guides to ensure the dough is the same thickness all over.
Cut out 2.5-inch cookies using your favorite cookie cutter. Place the cookies on a board and refrigerate the cookie cutouts for 30 minutes.
Bake the cookies at 300F for 20 minutes. The cookies will be lightly browned on the bottom. Let the cookies cool.
Combine the heavy cream, instant espresso, and milk chocolate and let the ganache cool until it's firm enough to pipe.
Use a pastry bag and a decorating tip to fill the cookies with a layer of chocolate ganache. Place a second cookie on top.
Once the cookie is filled add the second cookie on top and press down lightly to seal the cookie. Set aside and finish the remaining cookies.
The cookies are good at room temperature for 2 days (if they last that long) and then store them in the refrigerator.