Preheat the oven to 350 degrees F. Line two baking sheets with parchment paper.
In a large bowl with electric mixer, combine the brownie mix, flour, eggs, oil, and extract until combined.
Let sit for ~5 minutes. This will make it easier/less sticky to roll into balls.
Taking a cookie scoop, scoop out one dough ball and place a peppermint patty on top of it. Scoop out another dough ball and place on top of the peppermint patty and then press the dough around it, forming a large cookie.
Place 4-5 cookies onto each baking sheet, depending on how large your baking sheet is. They will spread, so place the cookies at least 2" apart.
Bake in the preheated oven for 10-12 minutes, until the tops are no longer wet looking. Be mindful not to over-bake! They will set up while they cool.
Let them cool on a baking sheet for about 10 minutes and then transfer to a cooling rack to cool completely.
Devour!