A really good scallop potato recipe is a treat indeed. My favorite version involves cups and cups of whipping cream and many knobs of butter, so I only make it when there is company and I have a great excuse.
This version however is far more guilt free with the substitution of buttermilk and the omission of excess butter. The result is a gently tangy potato gratin with melted leeks between the folds of potatoes. Serve with a great stew or braise.
Leek and Buttermilk Scallop Potatoes(serves 6)
Finely slice the leek into rounds and wash very thoroughly in cold water. Heat a medium skillet to medium low heat. Add the olive oil and the leek along with a pinch of salt. Sweat the leek and str until soft. Remove from heat and allow to cool.
Preheat the oven to 400F. Combine the salt, buttermilk, pepper and two thirds of the cheese in a large bowl. Wash the potatoes and peel them. Hold the potato in a bowl of cold water as you peel the rest so they don't turn black. Finely slice (I prefer a mandolin) the potatoes, and as you slide them add them to the bowl of buttermilk. Toss with the leeks and add into an oven safe casserole. Sprinkle remaining cheese on top and more fresh pepper.
Transfer to the oven and bake for one hour. Test with a toothpick, if you feel resistance when poking the potatoes continuing baking until quite soft (possibly another 30 minutes). Allow to cool for 15 minutes before slicing and serving.