Comfort cookies

I once found a recipe a couple years ago in a Pick n Pay fresh Living magazine, which – after a couple alterations – has become my staple cookie recipe.
I make the basic cookie recipe, divide the dough in half to make one chocolate and one plain, roll them together and create beautiful swirly cookies.
All my good friends know them well, and in a way they have become my signature biscuits.
They're also quite easy to make and cost effective.

Here is the recipe:

180g or room-temperature butter
300g caster sugar
1 extra-large egg
1 extra-large egg yolk
pinch salt
380g flour
2 heaped tablespoons of cocoa powder

First, cream the butter, then slowly add the sugar and mix until well blended. Stir the yolk and whole egg in with a wooden spoon. Add the pinch of salt and add the flour in 100g bits. If you see the mixture is a bit dry after 300g additions, add only another 50g of flour (making it 350g of flour). Divide the dough into two. Work at both of them with your hands until they form a nice ball of dough.
Coat counter with flour.  Roll out one half with a rolling pin.
Place the other half back in the bowl with the cocoa powder and knead it in with your hands until evenly distributed and dough is chocolate brown.
Add more cocoa powder if desired.
Roll out the cocoa dough. Once flat, wrap it around the rolling pin and place it over the rolled out plain dough.
Roll the doughs up to form a long dough sausage.
Cover in cling film and refrigerate for half an hour.
Remove from fridge, slice into 5mm slices, place on buttered baking tray.
Bake the cookies for 12-15 minutes until slightly golden in an oven preheated to 180 degrees Celsius.
Voila!