1. Heat a large nonstick skillet over medium-high heat. Coat pan with cooking spray. Add mushrooms and garlic to pan; sauté 5 minutes or until tender, stirring frequently. Combine mushroom mixture, turkey, potatoes, 1/4 cup panko, cheese, onions, thyme, salt, and pepper in a large bowl. Divide mixture into 8 equal portions, shaping each into a 1/2-inch-thick patty. Refrigerate 10 minutes. Dredge patties in remaining 1/2 cup panko.
2. Heat 1 1/2 teaspoons oil in a large nonstick skillet over medium-high heat. Add 4 patties; cook 2 minutes on each side. Repeat procedure with the remaining 1 1/2 teaspoons oil and remaining 4 patties.