Serves 4 to 6
1 1/2 pounds small red potatoes, rinsed thoroughly
1 large (or 2 medium) leeks, prepared according to steps below
4 tablespoons butter
Salt and ground black pepper
To prepare the leeks:
Trim leek’s dark outer leaves with scissors. Quarter leek(s) lengthwise up to but not through the root and thoroughly wash. Remove and discard root, and then slice quartered leek(s) into a medium dice.
Cover potatoes with water in a Dutch oven or soup kettle. Bring to a boil, lid ajar, then simmer until a skewer inserted into the potato can be removed with no resistance, 15 to 20 minutes.
Meanwhile, heat 2 tablespoons of the butter in a medium skillet over medium heat. Add leeks; cook until tender, about 10 minutes
Drain potatoes, reserving 1/2 cup of the potato cooking liquid. Smash potatoes until lumpy with a large fork. Add remaining butter, leeks, and enough cooking liquid to form mashed potato texture. Season to taste with a generous sprinkling of salt and pepper. Continue to stir and mash until potatoes are part lumpy, part smooth. Adjust seasonings and serve.