Loaded Beef Stew with Mashed Potatoes

Name: Loaded Beef Stew with Mashed Potatoes
Ingredients: 1 tablespoon vegetable oil; 1 lb chuck stew meat, cut into bite-sized chunks; 1 medium onion, chopped (about 1 cup chopped); 2 medium carrots, sliced into medallions and halved; 1 stalk celery, finely chopped; 2 garlic cloves, minced; 2 tablespoons all-purpose flour; 2 tablespoons tomato paste; 1/2 cup marsala wine; 2 1/2 cups chicken stock; 1 tablespoon soy sauce; 1 tablespoon chopped fresh parsley; 1 teaspoon chopped fresh thyme or 1/2 teaspoon dried; 1 1/2 pounds yukon gold potatoes, peeled and cut into chunks; 1/4 cup (1/2 stick) unsalted butter; 1/4 cup heavy cream; 1 teaspoon kosher salt