Recipes Ingredients Meat & Poultry Beef Recipes Roast-Beef Sandwich 1.8 (9) 1 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 Prep Time: 10 mins Total Time: 10 mins Servings: 1 Check our recipe for Roast Beef with Caramelized Shallots and use leftovers for this sandwich. Ingredients For the Sandwich 1 onion roll, halved ½ cup mixed greens 3 ounces thinly sliced leftover Roast Beef with Caramelized Shallots 2 thin slices red onion 2 cornichons, (or gherkins), halved lengthwise For the Spread 1 tablespoon reduced-fat mayonnaise 1 teaspoon prepared pesto 1 teaspoon grainy mustard Coarse salt and ground pepper Directions Make spread: Mix together mayonnaise, pesto, and mustard; season with salt and pepper. Layer bottom roll half with spread, greens, beef, onion, and cornichons; top with other roll half. Rate it Print