Method
1. Pre-heat oven - 170°C
2. Line a clean baking pan with parchment paper
3. Add all purpose flour and powdered sugar to a clean large mixing bowl
4. Whisk until combined
5. Add unsalted butter
6. Mix until mixture comes together
7. Pat the mix into the pan to form the base
8. Bake baking pan until light golden - 20 min, 170°C
9. Add superfine sugar, lemon, all purpose flour and egg to a clean large mixing bowl
10. Beat until smooth
11. Pour filling into base
12. Reduce oven temperature to 160°C
13. Bake until just set - 25 min, 160°C
14. Let cool
15. Cut
16. Sprinkle with powdered sugar