4 lb. russet potatoes (about 8 medium), scrubbed
2 Tbsp. extra-virgin olive oil or bacon grease
1 Tbsp. salt
1½ tsp. freshly ground pepper, plus more
1 pound home-made bacon bits (buy them here)
12 oz. sharp white cheddar, coarsely grated (about 3 cups)
4 oz. Chèvre cheese, cut into ½” pieces (buy it here)
1¼ cups heavy cream
½ cup (1 stick) unsalted butter, cut into ½” pieces
⅓ cup sour cream
1¼ cups finely chopped scallions (from about 1 bunch), plus more thinly sliced for topping
1 tsp. garlic salt (buy it here)
6 cups lard (optional; for frying potato skins)(buy it here)
Preheat oven to 375°. Peel 4 lb. russet potatoes (about 8 medium), scrubbed. Save the peels if you want to make crispy potato skins (see below). Cut your potatoes into small, one inch pieces and spread on a greased (with olive oil or bacon grease), rimmed baking sheet. Toss potatoes with oil, salt and pepper. Bake in the oven until tender enough to be pierced with a fork.
Meanwhile, cook the bacon and cut into one inch pieces. Place on a paper towel to cool.
When cooked, transfer the potatoes to a large bowl and add the bacon, grated cheese, chèvre (cut into small pieces), heavy cream, butter, sour cream, scallions, and garlic salt. Using a potato masher, mash the ingredients together until blended. Add salt and pepper to taste.
Transfer potato mixture to a large ovenproof twelve inch skillet, or 13×9″ baking dish, spread into an even layer, and place on a rimmed baking sheet. Bake until top is golden brown, 30–40 minutes.
If making the crisped potato skins: place potato peels in a bowl and pour in cold water to cover. Soak 15 minutes, then drain and pat dry.
Heat 4 inches of lard in a large Dutch oven or other heavy pot to 350°. Working in several batches, fry potato skins until crisp and golden brown, about 4 minutes per batch. Transfer potato skins to a wire rack set inside another rimmed baking sheet to drain and immediately season with salt. Let cool.
Top casserole with diced scallions and crisp potato skins just before serving.