Recipe for pure shortbread biscuit:

Ingredients:
Plain flour (150 grams)
Butter not margarine(100 grams)
Icing sugar (50 grams)
Powdered milk(1/2 cup or more depending on how rich you want it to be)

Preparation:
Mix the butter and icing sugar together until creamy. Note not too much icing sugar, be careful of your measurement.

Sieve the plain flour + powdered milk into the bowl and mix thoroughly until well incorporated.

Form a ball with the dough and leave to rest in the fridge or in a cool place for 30mins

Preheat the oven at 170C/325F for about 5mins

Then place the dough on a table and roll it out to 3/4 inch thick width, then cut into 2cm by 10cm shortbread fingers or shape and gently transfer unto a baking tray.

Using a toothpick make indents on the shortbread fingers.

And finally place the tray into the preheated oven and bake at 170C/325F for 10 to 12mins or until firm, but not brown.

Note: more milk makes it more richer.