Preheat oven to 350 degrees. Place hazelnuts in 15 1/2 x 10 1/2 jellyroll pan. Bake 20 minutes, or until toasted. Wrap hot hazelnuts in a clean cloth towel. W ith hands, roll towel back and forth to remove skins. Coarsely chop hazelnuts.
Grease and lightly flour 2 large cookie sheets.
In large bowl, combine flour, sugar, baking powder and salt.
In a small bowl, with a wire whisk or fork, beat 4 whole eggs and 1 egg yolk (r eserve egg white for later use), vanilla and 1 tablespoon water. Pour egg mixtu re into flour mixture, stir with wooden spoon, then use hands to knead dough to gether. Dough will be very stiff. Knead in hazelnuts and cranberries.
Divide dough into 4 equal pieces. On lightly floured surface, with floured hand s, shape each piece of dough into an 11 x 2-inch log. Place 2 logs, about 4 inc hes apart, on each cookie sheet. With fork, lightly beat remaining egg white. W ith pastry brush, brush the egg white onto the logs.
Place cookie sheets on two oven racks. Bake for 40 minutes or until toothpick c omes out clean. Rotate cookie sheets between upper and lower racks halfway thro ugh cooking time. During baking, logs will spread and become loaf-shaped. Let l oaves cool 10 minutes on cookie sheet on a rack.
Remove loaves to cutting board. With a bread knife, cut each loaf crosswise int o 1/2-inch thick slices. Place slices cut-side down on same cookie sheets on ov en racks. Bake slices 10 to 15 minutes to allow Biscotti to toast. Rotate cooki e sheets between upper and lower racks halfway through baking time.
Remove Biscotti to wire rack. Cool completely. Biscotti will harden as they coo l. Store in tightly covered container.
Ida Shires