Preheat oven to 425°.
Place an 8-inch cast-iron skillet over medium-high heat until hot. Add ham, and sauté 2 minutes or until lightly browned. Place ham in a large bowl; set aside. Keep skillet hot.
Add muffin mix and remaining 3 ingredients to ham, stirring just until moist. Pour batter into preheated skillet. Bake at 425° for 15 minutes or until lightly browned.