Preheat your oven to 350°F (175°C) and prepare two baking sheets lined with parchment paper.

Melt 215g dark chocolate with 100g unsalted butter in a bowl over low heat until glossy.

In a stand mixer, whisk together 2 cold eggs, 150g granulated sugar, 100g light brown sugar, and 1/2 tsp salt for about 5 minutes until fluffy and pale.

Sift together 200g gluten-free flour blend, 10g cocoa powder, and 50g hot cocoa mix.

Slowly combine the melted chocolate mixture with the egg mixture on low speed.

Fold in the sifted dry ingredients gently until no dry streaks remain.

Scoop the dough onto the prepared baking sheets and top each scoop with a spoonful of marshmallow fluff, swirling it into the dough.

Bake for about 11 minutes until crinkled on top and slightly domed.

Shape cookies with a round cutter immediately after removing from oven.

Cool on baking sheets for 5-10 minutes before transferring to a wire rack.