Guess that would depend on what tools you have at your disposal and are these cabinet doors being built, and still in pieces (rails and styles) or in one piece frame.
I did each rail and style of my cabinet doors on my router table. Used a 1/4" bit, set my fence where the bit would be in the center of my 3/4" lumber and cut. Stopped my rails a 1/2" or so from the ends, so the groove didn't show on the outside of doors. Styles, through and through.