Food & Cooking Recipes Appetizers Apple-Onion Tarts 4.0 (20) 5 Reviews By Martha Stewart Test Kitchen Martha Stewart Test Kitchen The recipes developed by our test kitchen team have undergone a rigorous process of development and testing, ensuring that every element is optimal, from ingredient amounts to method and cooking time. This process includes triple-testing recipes to ensure they meet our high standards. The many stellar cooks and food editors who have been part of our team include Sarah Carey, Lucinda Scala Quinn, Jennifer Aaronson, Shira Bocar, Anna Kovel, Greg Lofts, Riley Wofford, Lauren Tyrell, and Lindsay Leopold. Editorial Guidelines Updated on June 12, 2017 Print Rate It Share Share Tweet Pin Email Photo: John Kernick Servings: 6 These apple-onion tarts have a rosemary-infused, parsnip sweetened crust. Ingredients 1 tablespoon extra-virgin olive oil 1 tablespoon unsalted butter 3 medium Gala apples, peeled, cored, halved, and sliced ¼ inch thick 8 medium yellow onions, halved and thinly sliced 3 tablespoons cider vinegar ½ teaspoon coarse salt All-purpose flour, for dusting Rosemary-Manchego Tart Dough 1 cup coarsely grated manchego cheese (2 to 3 ounces) Freshly ground pepper, to taste Directions Heat oil and butter in a large skillet over medium-high heat. Add apples and onions, and cook until golden brown, about 15 minutes. Cover, reduce heat to low, and cook until very soft and caramelized, about 35 minutes. Add vinegar and salt, and cook 5 minutes. Let cool. On a lightly floured surface, roll out dough to a generous 1/8 inch thick. Cut out six 7-inch rounds, gathering scraps and rerolling dough if needed. Place on parchment-lined baking sheets. Puree half the apple-onion mixture in a food processor until smooth. Using an offset spatula, spread 3 tablespoons apple-onion puree over each dough round, leaving a 1-inch border around edges. Sprinkle each with 2 tablespoons cheese. Season with pepper. Top each with a generous tablespoon of remaining apple-onion mixture, and sprinkle with 2 teaspoons cheese. Fold edges of dough in, crimping with your fingers. Refrigerate until chilled, about 30 minutes. Meanwhile, preheat oven to 350 degrees. Bake until edges are golden brown, 40 to 45 minutes. Serve tarts warm or at room temperature. Rate it Print