Preheat Oven & Prep. Start by preheating the oven to 400 degrees F. Set out two cookie sheets and line with parchment paper.
Cream Butter, Sugar, Vanilla & Almond. In a large bowl, or the bowl of a stand mixer, cream softened butter, 1/2 cup powdered sugar, and the vanilla and almond extracts on medium speed 2-3 minutes, or until creamy and smooth.
Add Flour, Pecans, Cornstarch, and Salt and gently mix on low speed until just combined and the dough starts to come together.
Scoop & Roll. Use a small cookie scoop to measure 1 Tablespoon balls of cookie dough. Smooth each ball of dough out between your hands and place 9-12 cookie dough balls on a baking sheet. (Leave the rest of the dough to rest at room temperature)
Bake Cookies 9-11 minutes, or until the bottoms just turn golden brown and the tops of the cookies have just started to crack. Let the cookies cool 3-4 minutes on the baking sheet before transferring to a wire rack to finish cooling. Repeat this baking process until all cookies are baked and cooled, alternating baking sheets with each batch so you don't put cool cookie dough on a hot baking sheet.
Roll In Powdered Sugar. When the cookies are cooled, gently roll each cookie in powdered sugar to coat well. (I do this one cookie at a time, and fluff the sugar up after every few cookies) Repeat until all cookies are coated in powdered sugar.
Serve & Store. Enjoy cookies right away or store in an airtight container at room temperature 2-3 days. To freeze, store cookies in a single layer in a freezer container up to 2 months. (You can also freeze the cookies once they're cooled but before you toss them in powdered sugar. Let the cookies thaw, then roll in powdered sugar before serving.)