In a large bowl combine cornmeal, flour, sugar, baking powder, and salt. Stir and set aside. In a medium bowl, combine melted butter, milk, egg and Greek yogurt. Stir until fully combined. Pour liquid mixture into dry mixture. Stir until fully incorporated. Pour into a greased 8 x 8 inch baking pan
. Bake for 20-25 minutes or until golden brown.