Now add salt and crushed black pepper, mix well. Add sweet corn and chopped spinach, mix well. Let it cook for further 6-7 minutes. When milk is thick in consistency add cheese slice and mix well. Cook for another 2-3 minutes keeping it stir so that no lumps can form. Filling is ready, switch off the flame, cover the pan and keep aside. And let it cool down to room temperature. You can refrigerate this filling for later use as well.