Preheat the oven to 325ºF. Position a rack in the center of the oven. Spray baking sheet (about 18" x 13") with baking spray or line with parchment paper or a Silpat mat.
In a large bowl, whisk together the flour, baking powder, salt, and spices.
In a medium-sized bowl, beat the melted butter and light brown sugar.
Add in the eggs one at a time. Beat for 2 to 3 minutes, until thick and pale.
Beat in the pumpkin puree.
Add the flour mixture to the mixing bowl a little bit at a time.
Let the dough rest a couple of minutes in the mixer bowl.
Scrape out the dough with a rubber spatula onto a clean counter. Since there is pumpkin puree, the dough may be a little sticky.
Work the dough on a clean counter with a little bit of flour until it is firm enough to transfer to the prepped cookie sheet. lined cookie sheet (I used a sheet for each log) and divide the dough in half.
When you can get the dough into a ball, transfer to a lined cookie sheet (I used a sheet for each log).
Spray hands with baking or cooking spray. Divide the dough into two equal pieces, then shape each into 2 flattened logs, about 3 inches wide and 12 inches long.
If you are using one baking tray, place logs a few inches apart on the baking sheet so they won’t stick together as they bake. If you have two sheets, place one log on each lined baking sheet.
Use a sharp knife to score the logs. Be sure to not cut all the way through (this step is optional, but nonna always scores her biscotti logs).
Bake until dough is firm but gives slightly when pressed, about 20-25 minutes.
Transfer sheet to a wire rack and let logs cool until you can touch to cut with a knife (should take 15 minutes...sometimes I only wait 10 minutes).
Reduce oven temperature to 300 degrees.
Transfer the first loaf carefully to a cutting board. When the logs have cooled down, begin slicing the first log by pressing a very sharp knife or serrated knife into the dough (if using a serrated knife, cut with a with a sawing motion).
Keep in mind that when you slice on a bigger angle, you will get much longer cookies. If you slice short angles, you’ll get small biscotti.
Place the cookies back on the baking sheet, cut sides up.
Place the second log on the cutting board and repeat process cutting out the cookie pieces and placing on the baking sheet.
Bake 7 minutes, flip biscotti, and bake 7 minutes more.
Set the sheet on a rack to cool completely.
While the biscotti cool down, prepare the icing (if you’re using).
To make the icing:
The icing is optional. Add powdered sugar in a bowl and stir in maple syrup (or milk, use unsweetened almond or coconut milk if you're dairy-free) until the desired consistency is reached.
To test the consistency, let the glaze pour off the spoon. The glaze should fall into a ribbon and hold the shape for a few seconds before melting back into the glaze.
If the glaze is too thick, add a drop of water and test again. If the glaze is too runny, add a little more powdered sugar.
To decorate cookies:
Transfer the icing into a squeeze bottle, or a piping bag with small round tip, or a plastic zipped bag and cut a corner off. Decorate the cookies and let the icing set.