Preheat the oven to 325°F. In a large bowl, whisk together the flour, sugar, cocoa powder, and salt.

Add the butter, peanut butter, and vanilla. Use a pastry blender to incorporate the ingredients until the dough starts to come together.

Form the dough into a ball and knead until smooth. Roll the dough to about 1/3-inch thick and cut out cookies with cutters.

Place cutouts 1/2-inch apart on an ungreased cookie sheet. Bake for 15-20 minutes until centers are set.

Cool cookies on the sheets for 5 minutes, then transfer to a wire rack to finish cooling.

For the icing, melt chocolate chips with half the shortening in a microwave-safe bowl, stirring every 30 seconds until smooth.

Repeat the melting process with peanut butter chips and the remaining shortening.

Spread half of the cookies with chocolate mixture and the other half with peanut butter mixture. Drizzle with leftover icing.