Preheat the oven to 325F. Place the pecans on a cookie sheet. Toast in the oven for 4-5 minutes, until just fragrant. Take care not to let them burn.
Add the toasted pecans and all other ingredients to a food processor. Pulse several times until the dough looks crumbly, then process on high until the dough begins to come together. Press a bit of dough together between your fingers – if it holds together, the dough is ready. If not, blend a bit longer.
Use your hands to gather the dough together. Pinch off a little more than a tablespoon of dough and form a short rope of dough by squeezing the dough in the palm of your hand. Place the rope on a cookie sheet and shape into a crescent, smoothing any lumpy parts. Repeat until you have used all the dough. Bake the cookies for 25-30 minutes, until just barely firm to the touch. Let cool completely, then sift powdered sugar over the top of the cookies.