Place all dry ingredients for a baked recipe such as a cake into the food processor. Pulse the ingredients for several times for about 6 seconds each. This will aerate the flour and mix the dry ingredients together. It will also make the sugar finer and cause the cake to have a finer crumb.
My daughter hates to use a sifter. We always use a food processor instead of a sifter to aerate and mix the dry ingredients for a cake recipe. We originally got this idea from Alton Brown who also hates to sift.
Note: A food processor does not work for powdered sugar for icing. You must still use a sifter for the powdered sugar used in icing so that it will not contain any lumps, especially if you are using decorating tips to decorate the cake.