I found sweet potatoes in a steamer bag at my grocery store, but you can bake or microwave 2 large or 4 small till cooked. Set them aside till they cool a little, then take the skins off and cut the sweet potatoes into small pieces. I added the cut-up sweet potatoes to the immersion blender cup plus the maple syrup and butter. Pulse until it becomes a puree. It took me less than a minute to blend the ingredients. You can use canned sweet potatoes, but they are usually canned in syrup, so mash them and don't add the maple syrup or butter.
Weigh or measure the sugar and set aside. In another bowl, weigh or measure the flour, baking powder, baking soda, cinnamon, nutmeg, salt and run a whisk through to blend. In a stand or hand-held mixer, add the sugar and the butter and mix on medium speed for 2 to 3 minutes. Add the vanilla extract, maple syrup, sweet potato puree, and mix through. Break the egg into a small bowl (just in case some shells pieces break off) and add it to the rest of the wet mixture. Once blended through, turn the mixer down and slowly add the flour mixture till it is incorporated. Add the pecans and mix through for about 30 secs to a minute. Cover with plastic wrap and refrigerate for at least 45 minutes.
Preheat oven to 350° and line 2 cookie pans with parchment paper (I use parchment sheets). Using a medium cookie scooper, space out twelve scoops onto the cookie pan about 2" apart. This gives it space to spread and rise. Bake for 12-14 minutes. Leave the cookies on the baking pan for a minute or two before moving them to a cooling rack. This size batch makes about 2-½ dozen. Enjoy!