Take butter from fridge and allow to sit for about 30 minutes.
Chop butter into cubes and beat in a stand mixer on med-high for 1-2 minutes.
Add icing sugar and mix on low speed until combined. Turn speed to med-high and beat again for 1-2 minutes or until mixture turns a pale colour.
Add egg yolk and 3 teaspoons of lemon juice and combine with a spatula.
Fold through sifted flour and salt. The mixture should all be a pale yellow colour with no dry of floury parts. If it seems too dry, add another teaspoon of lemon juice.
Turn out mixture onto bench and knead lightly to form a ball. Wrap in baking paper and place into the fridge for at least one hour.
Pre-heat oven to 180 degrees celsius (fan-forced).
Remove mixture from fridge and break into two pieces. Roll out on a lightly floured surface to a thickness of about 3mm.
Use an 8cm round cutter (fluted works well), place rounds into ungreased muffin/cupcake tins.
Gently press into tin and then prick the base with a fork 3 times. Chill in the fridge for 10-20 minutes before placing a paper patty pan into each tin and fill with pie weights or rice.
Bake for 8 minutes and then remove patty pan and weights. Place back into oven and cook for another 2-4 minutes or until a light golden brown colour.
Allow to cool completely.