In a stand mixer or using an electric hand mixer, cream the butter until it's light and fluffy (approximately 1 minute).
Add sifted powdered sugar and continue mixing until fully incorporated.
Incorporate vanilla extract and cold water, mixing until combined.
Slowly add sifted flour in batches until fully combined, then add chopped pecans.
Cover the bowl with a tea towel and refrigerate the dough for 2 hours.
Preheat the oven to 325˚F.
Roll the chilled dough into bite-sized, evenly shaped balls using a 1 tablespoon cookie scoop.
Place the cookies on a parchment paper-lined baking sheet; they won't spread much, so you can arrange them closely.
Bake for 16-18 minutes on the middle oven rack. Once done, let them cool for 5 minutes.
In a medium-sized mixing bowl, add about ⅔ cup powdered sugar. Gently transfer each cookie to the sugar, rolling until coated. If preferred, sift powdered sugar over each cookie instead of rolling.