Preheat oven to 400 degree F. In a medium mixing bowl stir together the flour, cornmeal, sugar, baking powder, and salt. In another bowl combine eggs, milk, and melted shortening or cooking oil. Add the egg mixture all at one to the dry ingredients. Add jalapeno peppers, stirring together egg mixture and dry mixture just until moistened.
Place a greased 10-inch cast-iron skillet in the oven for 3 minutes. Remove from oven. Pour batter into hot skillet. (Or, pour the batter into an unheated, greased 9-inch round baking pan.) Bake for 20 minutes or until light brown. Remove from heat; set aside until cool enough to handle.
Cut cornbread into individual pieces. Brush lightly with melted butter. Grill directly over medium heat for 2 to 4 minutes per side or until marked. Makes 8 to 10 servings.