- 2 Tbs. unsalted butter, plus 1/2 tsp. for the dish
- 1 cup thinly sliced onions
- Kosher salt
- 2/3 cup heavy cream
- 2/3 cup chicken broth
- 2 Tbs. prepared horseradish (add more to taste if you like a strong flavor)
- Freshly ground black pepper
- 2 russet potato (24 oz.)
- 1/2 cup grated Bellwether Farms Pepato
Heat the oven to 350°F. Rub a shallow 2-quart gratin dish with 1/2 tsp. of the butter. Melt the 2 Tbs. butter in a small saucepan over medium heat. Add the onions; cook, stirring frequently, until softened, limp, and somewhat golden. Whisk together the cream, broth, and horseradish; add to the onions. Season with salt and pepper, stir to combine, and take off the heat.
Peel the potato, cut each in half lengthwise, and slice each across into thin half moons. In a large bowl, combine the potato slices, 2 teaspoons salt, the pepato, and the cream. With a rubber spatula, mix gently but thoroughly and scrape into the prepared gratin dish, pressing until evenly distributed. Bake covered for 30 minutes then remove cover. Cook until the top has browned and the potatoes are tender when pierced with a fork, about 30-45 minutes more. Let rest for 15 to 20 minutes before serving.