To make patties: Mix ground beef, rice, egg yolk, salt, pepper, garlic, Worcestershire sauce, parsley and thyme in a bowl. Shape into 4 oval patties about 3/4-inch thick. Heat olive oil in a large nonstick skillet set over medium-high heat. Sear patties about 3 minutes per side, or until a brown crust forms. Pour gravy over patties and simmer for an additional 10 minutes. Serve warm with mashed potatoes or noodles. Yield: 4 Servings.