Place a heat proof bowl over a pot of simmering water. Add the chocolate to the bowl and occasionally stir the chocolate until just melted and smooth.
Pour the melted chocolate onto a half sheet pan that has been lined with parchment paper. Using an offset spatula, spread the melted chocolate into a thin layer almost to the edges of the parchment paper.
Place in the freezer until frozen solid.
In the bowl of a stand mixer beat the butter until smooth, about 1 minute on medium speed.
Add the peanut butter, granulated sugar and brown sugar and beat on medium speed until light and fluffy, about 2-3 minutes.
Add the egg and vanilla and beat util combined.
Whisk together the flour, baking powder, baking soda and salt.
Add the dry ingredients and beat on low until just combined.
Remove the chocolate from the freezer and break into shards that are about an inch big. It's ok if some a smaller or larger, they should be random sizes. (See Video)
Add the shards of chocolate and gently fold into the cookie dough with a large rubber spatula.
Using a 1/4 cup scoop, portion out the dough. They should be about 60 grams each. Freeze until solid.
About 30 minutes before baking, preheat your oven to 350℉.
Place 6 frozen dough balls on a parchment lined half sheet pan, spaced evenly apart.
Bake for 15-16 minutes. Place the pan on a rack to cool .
If you want the cookies to be all uniform in size. Use a slightly larger round cookie cutter to scoot the cookies to a perfect circle immediately after removing from the oven.
After 10 minutes, place the cookies directly on the cooling rack and allow to cool completely.
