In a mixing bowl, cream the butter and sugar together for about 2-3 minutes.
Add eggs and vanilla and continue to beat the mixture for a few more minutes.
In a separate bowl, combine the flour, cocoa, baking soda and salt. Add the dry mixture to the butter mixture and mix just until combined.
Use a cookie scoop to scoop out a tablespoon of the dough and then press a peppermint patty into the center, using your fingers to shape the dough all the way around the peppermint patty. Bake at 350° for 8-9 minutes. Cool on baking sheets for at least 5-6 minutes and then carefully transfer to a wire rack to cool.