Preheat the oven to 350°F. Line a few baking sheets with parchment paper.
Beat the butter, shortening, powdered sugar, and salt in the bowl of an electric mixer on medium speed for 2 to 3 minutes, until the butter is the size of peas. Add the egg and mix until well combined. With the mixer on low speed, gradually add the flour and pecans and mix until just incorporated.
Using a small ice cream scoop, form the dough into small compact balls and place on the prepared baking sheets, spacing the cookies 1 inch apart. Bake for about 15 minutes, until firm to the touch and lightly browned around the edges. Remove from the oven and let cool for 5 minutes. Transfer the cookies to a wire rack and let cool completely.
Dust the tops of the cooled cookies with powdered sugar.