Method:

Whisk Butter and Sugar well.

Add egg to the batter.

Now add Flour, baking powder, sugar and fold.

Keep it in fridge for 10 - 15 minutes.

Pour the mixture in the piping bag, give it a shape and bake for 15 minutes.

For topping:
Add butter, caster sugar, water and cocoa powder in a bowl and mix well. After mixing place your pot on the stove and cook on medium hear, stir constantly until the butter melts, and mixture in a nice liquid form. Now turn off heat and let it cool for few minutes. Icing should be warn not boiling hot.

With a help of a spoon, pour the topping in the biscuits.

Tip. If you cant do shape with a piping bag use fork. I did shape with fork. Tip 2: put them in Jar to keep it crispy.. baasi na hojaye isliye.