2 pounds fingerling potatoes, scrubbed and cut into 1/2-inch rounds
1/4 cup extra-virgin olive oil
1/2 pound thickly sliced pancetta, cut into 1/3-inch dice
Salt and freshly ground pepper
1 onion, thinly sliced
1/4 cup finely chopped dill
Bring a large saucepan of water to a boil. Add the potatoes and cook until just tender, about 8 minutes. Drain and pat dry.
In a large cast-iron skillet, heat the olive oil. Add the pancetta and cook over moderate heat until lightly browned, about 3 minutes. Using a slotted spoon, transfer the pancetta to a bowl.
Add the potatoes to the skillet, season with salt and pepper and cook, stirring occasionally, until lightly browned, about 10 minutes. Add the onion and cook until softened and the potatoes are golden brown, about 10 minutes longer. Stir in the pancetta and cook for 2 minutes longer. Transfer the potatoes to a bowl. Toss with the dill right before serving.
The potatoes can be kept at room temperature for up to 4 hours. Reheat in a 325° oven before serving.