Sift together the flour, baking powder, and pumpkin spice. Set aside.
In a mixing bowl, cream together the butter and sugar. Add the pumpkin and the eggs, and beat until combined. Stir in the flour mixture, just until no streaks remain.
Stir in a half cup of the chopped pecans. Freeze the dough while the oven preheats.
Preheat the oven to 350 degrees.
Toast the other half cup of nuts on a sheet pan in the heated oven for five minutes. Finely chop the nuts and set them aside.
Line a sheet pan with parchment paper. Divide the dough into 4 loaves, about three inches wide, and an inch high. Bake until they're firm, about 30 to 40 minutes.
Remove the pan from the oven and slice the biscotti with a serrated knife into ¾ inch slices, and lay them flat on two parchment lined baking sheets. Reduce the heat to 300 degrees and bake the cookies for 15 more minutes or until they're crisp. However, these aren't super crispy biscotti, like some are. Cool the cookies on a rack.
In a small bowl place the chocolate and shortening and microwave for twenty seconds. Stir. Repeat this until the chocolate is completely melted.
Dip one end of each cookie in the chocolate and place on a wax paper lined pan. Sprinkle the chocolate with the nuts. Let the chocolate harden before serving.