In a medium bowl, whisk together the all-purpose flour, cocoa powder, baking powder, baking soda, and salt.

In a stand mixer, cream the room temperature unsalted butter, light brown sugar, and granulated sugar on medium speed for 3-4 minutes until light and fluffy. Incorporate the large egg, egg yolk, oil, and vanilla extract.

Gradually add the dry mixture to the wet ingredients, mixing on low speed until just combined.

Wrap the cookie dough tightly in plastic wrap and refrigerate for at least 5 hours, or ideally overnight.

Preheat your oven to 180°C (350°F) about 20 minutes before baking.

Scoop out small portions of dough and roll them into balls, then roll in turbinado sugar.

Freeze the rolled cookies for about 15 minutes to solidify them.

Bake in the preheated oven for 7-8 minutes.

For the salted caramel filling, melt the granulated sugar over medium heat until golden, then add unsalted butter, followed by heavy cream.

Spread a generous amount of caramel on one cookie, top with another, and press gently.