You will need a meat thermometer to make sure you cook your Wellington perfectly.

Pre heat your oven to 220°C. Place the Wellington (straight from the fridge) on a wire rack, and cook for 25 minutes.

Reduce the temperature to 160°C and cook until the internal temperature is 45°C when probed (for medium rare), approximately 15 minutes.

Allow to rest uncovered for 15 minutes before carving.