Pre-heat oven to 200°C/390°F or 180 FF
In a medium bowl, sift together the flour, cocoa and baking powder
In the bowl of a stand mixer, combine the 2 sugars on low speed
Add the butter and mix to combine
Add eggs and vanilla, then mix on a medium speed, until light and fluffy (approx 3 minutes)
Stop the mixer and add the flour mixture, along with the chocolate chips
Mix on low speed until just combined
Optional: chill the dough for 10 minutes, to make handling easier
Using a large ice-cream scoop, scoop out the dough and roll into balls
Using your thumb, place a dent into each ball, place 4-5 frozen marshmallows into the dent, then roll to enclose
Place cookie dough balls onto a tray lined with baking paper. Leave some space for spreading
Bake cookies for 8 minutes, then remove from oven and allow to cool on tray for 2 minutes, before transferring them to a rack to cool.°