4 large unpeeled Idaho potatoes (about 10 ounces each), well scrubbed
4 tablespoons unsalted butter (1/2 stick)
2 tablespoons olive oil
1 green bell pepper, seeds and membranes removed, finely chopped (about 3/4 cup)
2 medium shallots, peeled and minced
3 tablespoons minced Italian parsley
Heat oven to 375°F. Halve potatoes lengthwise and place, cut side up, directly on the oven rack. Roast until entire cut surface of potatoes has a golden-brown crust and the tip of a paring knife easily pierces the undersides, about 45 minutes. Let potatoes cool until they are easy to handle, then cut into large dice (you should have about 8 cups).
Melt butter with oil in a large, heavy frying pan over medium-high heat. When mixture foams, add bell pepper and shallots. Cook until vegetables are softened and edges are beginning to color, about 3 minutes.
Add potatoes, tossing to coat, and cook until heated through, about 6 to 8 minutes. Turn them only once or twice so that they have a chance to get crisp. Liberally season with salt and pepper, and toss with parsley.