01 -
Crank your oven up to 175°C (350°F) first. Slide those cookies in and leave them for 10 to 12 minutes. Let them hang out on the baking pan a few minutes, then move them to a cooling rack.
02 -
Drop scoops of both the chocolate and plain dough onto a lined sheet in turns. Grab a toothpick or something similar and twist through to make wavy stripes—don't overdo it if you want that zebra look.
03 -
Take your remaining dough half and stir in the cocoa powder until chocolatey all the way through.
04 -
Split your dough pile in two. Leave one part as is for plain vanilla.
05 -
Mix salt, flour, and baking powder in a new bowl. Slowly dump this into your buttery mix, blend just enough to get a dough that looks soft.
06 -
Toss in one egg, stir, then crack in the second egg and blend again. Pour in your vanilla, mix until it's all together.
07 -
Beat together that room temp butter and all your sugar in a big bowl with a hand or stand mixer. Keep going 'til it's fluffy and looks pale.