Shortcrust pastry

Ingredients
2 cups all-purpose flour
2 tbsp custard powder
1/3 cup white sugar
185gm butter
1 egg yolk
2 tbsp cold water
1 teaspoon vanilla extract

Method :-
1. crumble flour, custard powder, sugar and butter till fine
2. add in egg yolk and just enough water to bind
3. chill and use