2 1/4 pounds small Yukon Gold potatoes, scrubbed but not peeled
1 teaspoon yellow mustard seeds
4 tablespoons unsalted butter, softened
1 tablespoon minced parsley
1 medium shallot, minced
2 teaspoons fresh lemon juice
Salt and freshly ground pepper
In a saucepan, boil the potatoes in water to cover until tender, about 15 minutes.
Meanwhile, in a small skillet, toast the mustard seeds over moderate heat until they pop, about 3 minutes. In a small bowl, mix the butter with the parsley, shallot, lemon juice and mustard seeds. Season generously with salt and pepper.
Drain and halve the potatoes lengthwise. In a large dish, toss the potatoes with the shallot butter and serve.
The shallot butter can be refrigerated for 1 week.