Preheat oven to 350.
Pour the flours into a big bowl and make a well in the center large enough to place the sugar, 3 of the 4 eggs, the 2 egg yolks, the baking powder, salt, vanilla and anise seed.
Gently knead the dough for 5 minutes, This is a hard dough so it needs to be convinced to gather together (I have used my kitchen-aid mixer with the dough hook with good results).
Slowly add the nuts (almonds are my favorite) and keep on kneading until well incorporated, You may need some additional flour to keep it from sticking to the bowl.
Butter and flour 2 cookie sheets that are at least 15 inches, Divide the dough into 4 even pieces and roll each one into a log, Place the logs well apart, 2 to each sheet,.
Beat with the remaining egg and brush the top of the logs with egg.
Bake the biscotti loaves for 35 minutes.
Remove from the oven and reduce the oven temperature to 325.
Slice the biscotti and return to the oven for an additional 15 minutes of baking time, Cool on racks.
Variations: Melt a couple of bars of Gianduia chocolate or any Italian chocolate with nuts or praline in it, melt in a double boiler with a teapsoon of vegetable shortening, Dip half the biscotti into the chocolate and put it on a cooling rack until the chocolate hardens.