Preheat the oven to 375°F. Line two baking sheets with parchment paper.
In a large bowl, whisk together the flour, cocoa powder, baking soda, and salt. Set aside.
In a large mixing bowl or bowl of the stand mixer fitted with the paddle attachment, add the shortening, peanut butter, 1/2 cup (100 g) sugar, and brown sugar. Beat with a hand mixer or the stand mixer until light and fluffy.
Add the milk and vanilla and beat until well combined.
Add the flour mixture to the peanut butter mixture. Mix until just combined.
Place the remaining 1/4 cup (50 g) of sugar in a small bowl. Roll tablespoon-sized (~18 g) balls of dough in the sugar and place on the baking sheet.
Bake for 7-9 minutes, until lightly golden. Once you remove the cookies, press into the centers of the cookies with a 1 teaspoon measuring spoon.
Add the chocolate chips and coconut oil to a microwave-safe bowl and microwave in 30 second intervals until melted, stirring in between.
Place a dollop of chocolate into each cookie divot and leave at room temperature or refrigerate until set. Enjoy!
