Preheat the oven to 170°C and roast the pecans for 5 minutes.

Chop the roasted pecans into small pieces and set aside.

Cream the softened butter with brown and white sugars until well combined.

Add the egg and vanilla extract to the butter mixture and mix well.

Sift together the cake flour, cocoa powders, baking soda, and salt, then mix into the wet ingredients.

Fold in the dark chocolate chips and chopped pecans evenly.

Cover the dough with plastic wrap and refrigerate for 1 hour.

Divide the dough into 60-65g portions and wrap each portion around a marshmallow.

Place the dough balls on a baking sheet lined with parchment paper, leaving enough space between them.

Cover the tray with plastic wrap and refrigerate for another 30 minutes while preheating the oven.

Bake the cookies at 170°C for 8-10 minutes.

Carefully transfer the cookies to a cooling rack.