Cake flour vs. pastry flour vs. cake and pastry flour
Cake flour is a low protein flour that produces the tender crumb that's found in most cakes and cupcakes.
Pastry flour has just a touch more protein in it than cake flour, leaving your baked goods with a bit more texture--but still tender.
Cake and pastry flour falls right in between the two and is the professional baker's choice for a wide variety of cakes and cookies.
For the at home baker, your best is to use cake flour for cakes and cupcakes. If you want pastry flours (for biscuits and more), you can make your own by combining approximately 2 parts cake flour to 1 part all-purpose flour.