1.25kg washed red potatoes
2 stalks celery (175g), very thinly sliced
4 green spring onions, thinly sliced diagonally
½ cup small fresh mint leaves
¾ cup buttermilk
½ cup whole-egg mayonnaise
2 tablespoons wholegrain mustard
2 teaspoons lemon juice
Cut potatoes into 1cm thick slices. Place in a stockpot covered with cold water. Bring to boil. Gently boil, covered, for about 12 to 15 minutes, or until just tender when tested with the tip of a small, sharp knife. Drain.
Place potatoes in a large bowl. Stand for 15 minutes to cool slightly.
To make dressing, whisk all ingredients in a medium jug until combined. Season with salt and pepper.
Add celery, onions and mint to warm potatoes. Pour over dressing. Gently toss to combine. Serve.
TIP! Salad, omitting the celery, onions and mint, can be made up to three hours ahead. Keep, covered, in fridge. Toss through those ingredients just before serving.