If using a mixer, use the dough hook attachment and add the flour about 1/2 cup at a time. Continuing adding flour until the dough pulls away from the edge of the bowl and is just a little sticky to touch. Knead with the dough hook on low speed for about five minutes.
To knead by hand, stir in flour 1/2 cup at a time until it becomes to difficult to stir. Turn the dough onto a well-floured surface and continue to knead in the flour a bit at a time, until barely sticky to the touch.