Soak cereal in large bowl. Cover cereal with 2 cups boiling water and soak for 30 minutes. Add sugar to 1/3 cup water in measuring cup. Add yeast and stir gently with a small spatula until moistened. Let set until foamy, about 10 minutes. Add eggs, honey, oil and salt to the soaked cereal. Stir until blended. Stir in yeast. Mix in hazelnuts. Add 2 cups whole wheat flour and 1 cup unbleached flour. Beat until well blended. Continue adding unbleached flour until a stiff dough is formed. Turn out onto floured surface. Knead and continue to add unbleached flour until dough is smooth, elastic and no longer sticky.
Place dough in large bowl that has been oiled. Cover and rise in warm place until double, about 1 hour. Punch dough down and divide in half. Return half to oiled bowl. Braid remaining half by dividing it into 4 pieces. Roll each 21 inches long. Pinch ends together and tuck end under strands. Begin a standard 3-strand braid then slide the 4th strand under the new left. It becomes the left. First round completed, continue braiding and always finish a round by sliding the 4th strand under the left. Pinch ends together and tuck end under. Use large spatula to place braid on a greased cookie sheet. Cover and let rise for about 30 minutes.
Beat egg and water until white and yolk are thoroughly mixed. Brush braid with the egg wash. Bake at 350°F for 15 minutes. Reduce to 325°F and bake for about 30 minutes. Shape, let rise, and brush second half of dough while first braid is baking. Makes 2 loaves (16 pieces each).
