"Through her recipes, devoted entirely to what she describes as the 'elixir of the human race,' Diane draws you into the rhythms of life on a farm." —Thomas Keller, The French Laundry For anyone who's enjoying a return to real food, true buttermilk remains one of the great, undiscovered pleasures. Many people enjoy organic produce, grass-fed meats, and artisan breads, but "real" dairy has bee…