Ingredients. 
200g Room Temperature Unsalted Butter.
150g Caster Sugar.
1 Large Egg.
275g Self Raising Flour.
200g Cocoa Powder.
Splash Of Milk.

1 Bar Of Chocolate - Optional.

Step 1.
Cream together the butter and the sugar until it is light and fluffy.

Step 2.
Add in an egg and whisk together. 

Step 3.
Add in the self raising flour and cocoa powder. Mix together with a wooden spoon. 

Step 4.
At this stage you can add chunks of chocolate to the mixture. Saving a few squares for later.

Step 5.
If the mixture isn't forming a dough easily add in a splash of milk to help. 

Step 6.
Line two baking trays with baking paper and divide the mixture into 12 equal size balls. For this I used a 1/3 of a cup measuring cup to ensure they were all equal. Make sure to leave enough space for the mixture to expand. 

Step 7.
At this stage you can pop the left over chocolate on the top of the mixture. If not press the mixture down slightly. 

Step 8.
Pop in the oven for 10 minutes. 

Step 9. 
After 10 minutes the cookies will still be slight gooey but allow them to cool for 30 minutes.

Step 10. 
After 30 minutes the cookies will be crunchy on the outside and soft in the minute. Perfect to eat.