what is cake flour can anyone help?

cake flour is just a low protein flour.

For example, bread flour might be 14% protein, all purpose (plain) flour might be 10-12% protein and cake flour will be around 8-9% protein. Just use all purpose or plain if you cannot find it

Off the top of my head, there's nothing sensible I can think of that you might do to turn regular flour into cake flour. Although since cake flour is a finer grind than regular, I wonder whether whirring it in a blender would do any good...? In a jam, I've done this with granulated sugar to achieve a finer texture. It never got anywhere near as fine as powdered sugar, but it did help. Still, your best bet is to bite the bullet and go buy some cake flour. It's commonly available, and it does make a difference in your results!

This flour is made from soft wheat that forms weak gluten. Finely milled and bleached, cake flour is best for tender cakes and cookies. If you don't have cake flour, you can substitute 7/8 cup all purpose flour and 2 tablespoons of cornstarch for every cup of cake flour.