This recipe uses both leftover potatoes and leftover lamb. Try it with other leftover meat such as chicken or ham.
Combine the potato, onion, parsley and seasoning, divide into two and shape into a flattened cake shape; cook in hot butter in a non-stick frying pan until golden, then flip over and repeat.
In a bowl whisk together the egg yolk, mustard, garlic, lemon juice and soured cream. Add three-quarters of the oil slowly until emulsified, season.
Toss the lamb with the salad leaves and the remaining olive oil.
Place on top of the potato cake and dribble with the creamy garlic dressing.