We wanted a waffle recipe that produced crisp-on-the-outside, creamy-on-the-inside waffles. We found that a thick batter lets the outside of the waffle become crisp, while the inside remains custardy. Buttermilk made our batter extra thick.
Because crispness is so important in waffles, we tried substituting cornmeal for a bit of the flour in our waffle recipe and found that 1 tablespoon per cup of flour adds extra crackle.