1. Melt your butter, and then add the sugar(s) - mix well. 2. Add either 1 or 2 eggs (2 eggs makes the cookies slightly softer and more cake-like) and beat in. 3. Add vanilla extract and salt. 4. Sift in the flour, cocoa and baking powder and mix well (I just use a wooden spoon). 5. Finally, add the milk to make it a bit runnier. 6. Use baking trays to make your cookies by spooning a tall 'mountain' of mixture in whichever sizes you like. 7. Bake at 180C for 15 minutes and they should be perfect - should still slightly spongey to the touch. 8. If you like, you can add sprinkles before putting them in the oven.