Here’s a recipe to please both sweet potato lovers and regular potato fans! To make this in advance, cool the cooked components of the gratin before combining and assembling. Leave off the topping. Bring to room temperature, about 45 minutes, before topping with bread crumb mixture and baking. Gratin dish photographed by Jarrad Henderson in the Detroit Free Press studio on Thursday, November 1, 2012 in Detroit, Michigan.
1-1/2 cups lightly toasted panko bread crumbs or coarse fresh bread crumbs2 tablespoons unsalted butter, meltedPinch of kosher salt1 tablespoon Dijon mustard2 tablespoons Parmesan cheese or Parmigiano-Reggiano2 tablespoons chopped fresh flat-leaf parsley
GRATIN
2 tablespoons unsalted butter, plus 1/2 teaspoon for the dish1 cup thinly sliced shallots (6-7 large)2/3 cup heavy whipping cream2/3 cup fat-free, reduced-sodium canned chicken broth2 tablespoons prepared horseradishKosher saltFreshly-ground black pepper1 large russet potato (12 ounces), peeled1 large sweet potato (12 ounces), peeled1/3 cup grated Parmesan cheese or Parmigiano-Reggiano
To prepare the gratin: Preheat the oven to 350 degrees. Butter a shallow 2-quart gratin dish with 1/2 teaspoon of the butter. In a small saucepan, melt the remaining 2 tablespoons butter over medium heat. Add the shallots and a big pinch of salt; cook, stirring frequently, until softened, limp and somewhat golden. Whisk together the cream, broth and horseradish; add to the shallots. Season with salt and pepper, stir to combine and take off the heat. Peel both potatoes. Cut each in half lengthwise, and slice each across into thin half moons. In a large bowl, combine the potato and sweet potato slices, 2 teaspoons salt, Parmesan and shallot cream. Mix gently but thoroughly and scrape into the prepared gratin dish, smoothing and pressing until evenly distributed. Cover with the bread crumb topping. Bake until the crust is deep golden brown, the juices around the edges have subsided and the potatoes are tender when pierced with a fork, about 1 hour. Remove from oven and let rest for 15 minutes before serving. Recipe adapted from www.finecooking.com. Tested by Susan Selasky for the Detroit Free Press Test Kitchen.
