Food & Cooking Recipes Healthy Recipes Gluten-Free Recipes Roasted Onions and Rosemary Be the first to rate & review! 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 May 16, 2017 Print Rate It Share Share Tweet Pin Email Servings: 4 Roasted onions, sweet and slightly caramelized, are always a favorite vegetable side dish. Ingredients 3 medium red onions, quartered, leaving peel and root intact 2 tablespoons extra-virgin olive oil 3 small sprigs rosemary ½ teaspoon white-wine vinegar Directions Preheat oven to 450 degrees. On a large rimmed baking sheet, toss onions with extra-virgin olive oil and 3 small sprigs rosemary. Arrange onions, cut side down. Roast, without turning, until onions are browned on underside, about 15 minutes. Flip and roast until onions are tender, about 5 minutes more. Transfer onions to a serving dish and drizzle with white-wine vinegar. Rate it Print