Potato and white bean purée

1.Combine beans and plenty of cold water in a saucepan, simmer gently over medium heat until tender (25-30 minutes), drain and process in a food processor to a smooth paste. Return to pan and set aside.

2.Meanwhile, place potatoes in a large saucepan of cold salted water. Bring to the boil over medium-high heat, reduce heat to medium and simmer until tender and a skewer inserted meets no resistance (15-20 minutes). Drain and, when cool enough to handle, peel and pass through a moulis into bean purée (or mash well, then add to bean purée).

3.In a separate saucepan, heat cream and butter together until simmering, gradually add to potato mixture and mix until smooth. Season to taste and serve immediately with braised lamb shoulder.