• Into a large mixing bowl, add the cooled melted butter, granulated sugar, brown sugar, vanilla extract, and kosher salt, and mix with a whisk until well combined.
• Add the eggs, and mix until well combined and smooth.
• Sift the cocoa powder into the mixture and mix with a whisk until well combined.
• Add the flour and baking soda and mix until almost combined.
• Add the chocolate chunks and mix until just combined and there are no lumps of flour showing. Do not overmix the dough to keep these cookies fudgy!
• Cover the bowl with plastic wrap and let the dough rest in the fridge for at least an hour.
• Meanwhile, make the peanut butter filling. In a medium-sized mixing bowl, add the peanut butter, softened butter, powdered sugar, salt, and vanilla extract, and mix with a spoon until well combined and creamy.
• Preheat an oven to 180c (350f) and prepare a baking sheet with parchment paper.
• Use a cookie scoop to scoop out the cookies or scoop the cookies with a regular tablespoon, 1 ½ tablespoons at a time.
• Place the cookie dough balls onto a parchment paper-lined baking sheet and bake in a 180c (350f) preheated oven for 12-14 minutes.
• Let the cookies cool for 5 minutes, and then transfer them to a wire rack to cool completely.
• While you allow your cookie to cool, make the chocolate topping. Melt dark chocolate and heavy cream in a small to medium mixing bowl in the microwave for about 50 seconds.
• Let the chocolate and the cream sit for 10 minutes for the chocolate to melt, then mix until is smooth and silky.

Assembly

• Scoop the peanut butter mixture with a 1 tablespoon cookie scoop and roll it into a ball with your clean hands. Then flatten it out into a disk and layer each cookie with a disk of peanut butter. Press it down so it will stick to the cookie.
• Then, top the peanut butter layer with 1 teaspoon of the melted chocolate mixture and spread an even layer of it. Garnish with flakey salt if desired and serve!