On the larger side of a grater, grate the frozen butter directly into the flour mix. Stir the butter into the flour with a knife. Frozen butter is my secret ingredient. The colder the butter the flakier the pastry.
So remember, this is a shortcut short crust pastry, so we aren’t folding and doing that whole process. If you want to do it the old way, then you can fold it in thirds, roll out and place back in the fridge and then an hour later fold it again and roll it out again.