In separate bowl, mix butter and vanilla.
Mix flour, espresso, salt and powdered sugar.
Add flour mixture to butter mixture. Taste mixture. I had to add a tablespoon more butter (again), but you can leave it out if you feel it isn’t necessary.
Now put mixture into fridge for 15-30 minutes or until easy to handle. Roll out dough so it’s about the same thickness as the vanilla dough. (I didn’t actually do most of this, see above)