01 -
Combine the flour, cocoa powder, baking soda, and salt in a medium bowl.
02 -
Use a large mixing bowl to whip the butter, brown sugar, and white sugar until smooth. Add the egg and vanilla, stirring well to combine.
03 -
Slowly mix in the dry ingredient blend, about half at a time, on low speed. If needed, switch to a spoon to avoid flour clouds. Toss in the chocolate chips and give it a good stir.
04 -
Wrap the bowl with cling film and let the dough chill in the fridge for at least 3 hours or overnight.
05 -
Set your oven to 175°C and line baking sheets with parchment paper. Shape the dough into tablespoon-sized balls and position them about 5cm apart on the trays.
06 -
Bake a tray at a time in the center of the oven for 8-10 minutes, just until the tops feel slightly firm. Let them cool for 10 minutes on the tray before moving them to a rack.
07 -
Whip the butter in a big bowl until fluffy and airy. Add 180g of powdered sugar along with the salt and beat slowly, then faster. Gradually mix in the rest of the powdered sugar and cream until you like the texture.
08 -
After the cookies are cool, spread 1-2 tablespoons of frosting on the flat side of one cookie. Sandwich it together with another cookie, flat sides facing in.