Prepare muffin cups and heat oven to 425 degrees F. Combine the flour, cornmeal, sugar, baking powder, salt and baking soda. In another bowl, whisk together the sour cream, eggs and cooled melted butter. Add sour cream mixture to the dry ingredients and stir just until blended. Fold in corn and green onions. Fill muffin cups 3/4 full and bake 20 minutes or until done. If desired, add a can of diced green chiles (drained) or about 2 T minced jalapeno peppers.