Melt-in-mouth German Cookies

This is already the 5th week of school and the kids are adapting well, no one cried :-)

To keep my story short, here's just a quick update of what I've baked, German Cookies!  This is a very popular cookie in the cyberworld.  If you've been following me, you'll know I'm not a cookie person.  But since I've got a pack of near expiry potato starch, I didn't want to waste my ingredients so I made these.

Verdict: As per the title of this cookie, it truly melts in your mouth.  I made a few other versions but didn't have time to upload the pictures yet.

Melt-in-mouth German Cookies 德式酥饼
Adapted from Small Small Baker

Ingredients
(makes ~ 60 pieces)
125g butter
40g icing sugar, sifted (I used 30g)
125g potato starch
80g superfine flour (I use plain flour, tried out both 50g and 80g, both good)

Method

1. Beat butter and icing sugar till fluffy and lighter in colour.
2. Sift in potato starch and flour, mix to form a soft dough.
3. Roll into small balls (about 2cm in diameter), arrange on lined baking pan and press lightly with a fork (dip the fork in water after each press to prevent cookie dough from sticking to the fork). 
4. Bake in preheated oven at 170 deg C for 15 mins, upper rack (need not bake till cookies turn brown).