Mashed Potato Casserole With Sage and Fontina

Serves 8 to 10.

Note: This is perfect to make ahead, as the assembled unbaked casserole can be refrigerated overnight, then baked just before serving. Fontina is a good melting cheese; substitutes include Gruyère, provolone or Gouda. From “Potluck: Food and Drinks to Share With Friends and Family,” by the editors of Food and Wine magazine.

• 6 tbsp. unsalted butter, at room temperature, divided, plus more for greasing

• 3 lb. baking potatoes, peeled and cut into 2-in. pieces

• 1/2 c. crème fraîche (4 oz.)

• 2 tbsp. chopped parsley

• 1 tbsp. chopped fresh sage, plus 12 sage leaves

• 8 oz. fontina cheese, shredded (see Note)

• Kosher salt

• Freshly ground pepper

• 1/3 c. plain dry breadcrumbs

• 1/3 c. freshly grated Parmigiano-Reggiano cheese

• Olive oil, for frying

Directions

Preheat the oven to 400 degrees. Lightly grease a 2-quart shallow baking dish with butter.

In a large saucepan, combine the potatoes with enough water to cover by 2 inches. Bring to a boil and cook until fork-tender, 15 to 20 minutes. Drain well and transfer to a large bowl. Mash the potatoes with 4 tablespoons butter, the crème fraîche, parsley and chopped sage. Fold in the fontina and season with salt and pepper. Spread the potato mixture in the prepared dish in an even layer.

In a small bowl, using your fingers, blend the remaining 2 tablespoons butter with the breadcrumbs and Parmigiano until coarse crumbs form. Top the potatoes with the breadcrumb mixture. Bake for about 30 minutes, until golden and crisp on top.

Meanwhile, in a small skillet, heat 1/4-inch olive oil over low heat. Add the sage leaves and cook, stirring occasionally, until crisp, about 3 minutes.

Transfer the sage to paper towels to drain. Scatter the fried sage over the casserole and serve.