Preheat oven to 350 degrees F. Line baking sheets with parchment paper.
In a stand mixer, mix together butter and sugar until light and fluffy.
Add eggs and vanilla extract, mix again.
Add baking powder, mix again.
Add flour 2 cups at a time until all the flour is incorporated.
Put one cup of the dough on a parchment paper. Put another sheet of parchment paper on top and roll out the cookie to a 1/2 inch to 3/4 inch thickness.
Cut out the dough into 1 inch squares. Put on parchment paper.
Bake for 6-8 minutes. Check the bottom of the cookie to check for doneness. Cool on the baking sheet for 5 minutes before moving to a cooling rack.
Chocolate dip
Prepare a few parchment paper to put the dipped cookies.
Put chocolate chips and shortening in a wide shallow glass bowl in the microwave.
Heat about 1 minute. Be careful the bowl is hot. Stir until the chocolate becomes smooth and glossy. If there are still some lumps, heat up for another 20 seconds in the microwave.
Dip the cooled cookies in the chocolate diagonally and only half way. Place on the prepared parchment paper.