You are here: Home » Recipes » Potato Gratin with Spinach and Onions Potato Gratin with Spinach and Onions Recipe by Favorite Recipes Press Yield 10 servings A creamy cheesey au gratin potato dish with spinach and carmelized onions. PrintEmail Ingredients 1 3/4 pounds Yokon Gold potatoes -- Salt and pepper to taste2 large onions, cut into halves and thinly sliced1/4 cup water2 tablespoons extra-virgin olive oil8 ounces mushrooms, thinly sliced1 -- (10-ounce) package frozen chopped spinach, thawed and drained4 -- garlic cloves, minced4 teaspoons chopped fresh thyme1/4 teaspoon nutmeg1 cup nonfat sour cream1/2 cup reduced-fat milk -- Pepper to taste2 ounces Gruyere cheese, thinly sliced Instructions Combine the potatoes with enough salted water to cover in a saucepan. Bring to a boil. Boil for 30 minutes or until tender; drain and cool. Slice the potatoes 1/3 inch thick, removing any loose peel. Set aside. Combine the onions and water in a large non-reactive skillet. Cover and simmer for 12 minutes or until the onions are tender, stirring occasionally and adding more water by the tablespoonful if the onions are dry. Increase the heat to medium-high. Add the olive oil and mushrooms. Saute for 10 minutes or until the onions are deep golden brown. Add the spinach, garlic, thyme and nutmeg. Cook for 3 minutes, stirring constatnly. Remove from the heat. Stir in the sour cream, milk, salt and pepper. Layer half the potatoes overlapping slightly in a lightly oiled 7×11-inch glass baking dish. Season with salt and pepper. Layer half the spinach mixture over the potatoes. Continue layering the remaining potatoes and spinach mixture over the layers. Top with the cheese. Bake at 350F for 30 minutes or until hot and bubbly. Let stand for 5 minutes before serving. Recipe reprinted with permission from the Junior League of Saginaw Valley’s Between the Lakes (Junior League of Saginaw Valley, Saginaw, Michigan, 2005).