I got this from Pat Parker who runs a collection of frugal groups on Facebook and it works for me. it produces a pastry that's crisp on the outside and soft and fluffy on the inside and I really like it, not the least because it's dead easy. It does have its limitations but works well for topping pies.
half the weight of the flour in oil (so, for example, 50g flour and 25g oil)
some cold water
Mix the salt with the flour and mash in the oil. Add water and stir until the softish dough develops (not long). Wrap and chill.
It's very soft and I often pat it out with my fingers rather than roll it out.
I've only used this for the tops of things; must try it for the underneath at some point