I found this delicious and astonishingly simple salad in The Essential Jacques Pepin (Houghton Mifflin Harcourt 2011). The dressing on the potatoes and the butter from the shrimp rub shoulders with the escarole, which gets along with both, then the tarragon makes the whole thing sing. I've increased the potatoes a bit, as they're so good. It is meant to be a room-temperature salad, but it's good warm, too.
Makes 4 first-course servings
16 ounces small Yukon Gold potatoes, washed
1 teaspoon finely chopped garlic (2 cloves)
2 teaspoons Dijon mustard
Salt and freshly ground black pepper
1 1/2 tablespoons sherry vinegar
1/4 cup extra-virgin olive oil
1 tablespoon unsalted butter
1 pound large shrimp (16 to 20), shelled and cut in halves or thirds crosswise
1 1/2 teaspoons chopped fresh tarragon
1 1/2 teaspoons chopped fresh parsley
1/2 head escarole (8 ounces), as white as possible inside, trimmed, cut into 1-inch pieces, washed, and dried (about 4 cups)
Place the potatoes in a saucepan with enough water to cover them by 1 inch, and bring to a boil over high heat. Reduce the heat to low and boil the potatoes gently for 25 to 35 minutes, until they are tender when pierced with the point of a sharp knife. Drain and cool slightly.
When the potatoes are lukewarm, peel them and cut them into 1-inch cubes. Put them in a bowl, add the garlic, mustard, 1/2 teaspoon each salt and pepper, vinegar and olive oil and toss well. Set the potatoes aside to cool to room temperature.
At serving time, heat the butter in a large skillet. When it is hot but not smoking, add the shrimp and 1/8 teaspoon each salt and pepper and saute the shrimp for 1 1/2 to 2 minutes. Stir in the tarragon and parsley.
Add the escarole to the potato salad and mix well. Divide the mixture among four salad plates, sprinkle the shrimp on top, and serve.