How do you roll a short crust pastry that has been left in the fridge to relax overnight but is hard like piece of butter?

It sounds like your shortcrust pastry has gotten a bit too cold and hardened overnight. Here's how to bring it back to a workable consistency:

1. Warm It Up Gradually:

* Room Temperature: Take the pastry out of the fridge and let it sit at room temperature for about 30 minutes. This will allow it to soften slightly.

* Warm Water: If it's still too hard, you can gently warm it up using a bowl of warm water. Place the pastry on a plate and put the plate on top of the bowl of warm water. This should help to soften it without over-warming it.

* Microwave (with caution): In a pinch, you can try microwaving the pastry for a few seconds, but this should be done very carefully to avoid over-heating it. Start with 5-second bursts, check the pastry's consistency, and repeat as needed.

2. Re-roll Carefully:

* Use Parchment Paper: Once the pastry is slightly softened, roll it out between two sheets of parchment paper. This will help to prevent it from sticking to the work surface.

* Gentle Pressure: Apply gentle pressure when rolling, as hard pastry can crack easily.

* Avoid Over-Working: If the pastry feels too tough, let it rest for a few minutes before trying to roll it again.

Tips to Prevent Hardening:

* Wrap Tightly: Make sure the pastry is wrapped tightly in plastic wrap or placed in an airtight container before refrigerating.

* Use a Cooling Rack: If you have a cooling rack, you can use it to help air circulate around the pastry, preventing condensation from forming.

If All Else Fails:

* Crumble It: If the pastry is too hard to roll, you can always crumble it and use it in a crumble topping or a pie crust.

Remember, patience is key when working with pastry. Don't rush the process and the pastry will eventually soften to a workable consistency.