heat oven to 375, spray a roasting pan w/ cooking spray. Pound chicken breasts to 1/4"-thick. Spread each breast w/ mustard. Sprinkle w/ thyme, salt & pepper. Layer each breast w/ ham and cheese slices. Roll up each breast, secure w/ toothpicks. In bowl, pour panko crumbs, roll each chicken breast in panko crumbs. Sprinkle each breast w/ paprika. Place chicken, seam-side down in pan. Bake, uncovered for 30 min. Remove toothpicks and serve.