Preheat the oven to 350 degrees F. Line baking sheets with parchment paper.
In the bowl of a stand mixer fitted with the paddle attachment or using a handheld electric mixer, combine the granulated sugar, brown sugar, butter, baking soda and salt, and mix until light and fluffy, 2-3 minutes.
Add the eggs and vanilla and mix until well-combined, scraping down the sides of the bowl as needed.
Add the flour and cocoa and mix until combined.
Scoop the soft dough into about 2 tablespoon-sized mounds onto a parchment-lined baking sheet. Roll into balls.
Bake for 9-10 minutes until the cookie is set around the edges and has a few crackles on the edges and top.
Let the cookies cool completely.
For the frosting, whip together the butter and peanut butter until creamy and smooth, 1-2 minutes.
Add the powdered sugar and mix on low speed until mostly incorporated.
Add the salt, vanilla and heavy cream and mix until light and fluffy, 1-2 minutes.
For the chocolate ganache, place the chocolate chips in a medium bowl. Heat the cream until just below a simmer. Pour over the chocolate chips and let sit for 4-5 minutes. Stir until smooth and glossy.
Frost each cooled cookie with peanut butter frosting followed by a dollop of chocolate ganache.
Refrigerate the cookies or serve at room temperature.
