Ingredients
4 lg. Kennebec or baking potatoes, cut into 1/2 in. thick rounds
salt
Pepper
1 Stick unsalted butter
3 tbsp. seasoned rice vinegar
2 tbsp. mustard seeds
1/4 c. sherry vinegar
2 tsp. pure maple syrup
2 tsp. lemon juice
1/4 c. rice bran or canola oil
2 celery ribs, thinly sliced
4 scallions, thinly sliced
Preparation
Step 1In a large saucepan, cover the potato rounds with water and bring to a boil. Add a generous pinch of salt and simmer over moderate heat until the potatoes are tender but not falling apart, about 12 minutes. Drain and transfer to a baking sheet to cool.Step 2Light a grill or preheat a grill pan. Lay 2 large sheets of heavy-duty foil on a work surface. Fold up the edges to form a 1/2-inch rim and pinch the corners together to seal. Transfer the foil to the grill and melt the butter on it. Add the potatoes in a single layer and grill over moderate heat until browned on the bottom, 12 to 15 minutes.Step 3Meanwhile, in a small saucepan, bring the rice vinegar just to a boil. Add the mustard seeds and let cool completely. Whisk in the sherry vinegar, maple syrup, lemon juice and rice bran oil. Season the dressing with salt and pepper.Step 4Transfer the potatoes to a large bowl. Add the celery, scallions and dressing and gently toss to coat. Season with salt and pepper and toss again. Serve right away.
