How to make the perfect shortbread cookies and the common mistakes to avoid

The king of cookies, shortbread or sugar cookies should be crisp but tender 

One you've mastered shortbread, you'll never buy a packet of biscuits again. 

There is no room to hide

Shortbread has so few ingredients that it is extremely important to use top-quality ingredients. Use real butter and make sure your flour is not stale (it will smell slightly musty when you open the bag).