TOAST PECANS: Preheat the oven to 350 degrees F. Spread the pecans in an even layer on the sheet pan. Bake for 5-7 minutes or until they smell fragrant. Watch carefully-- you don't want to burn them. Remove from the oven and allow to completely cool before transferring them to a mini food processor or cutting board. Pulse on the "chop" setting or finely chop. You want very small pieces, but avoid over-pulsing in the food processor or you'll end up with pecan butter.
WET INGREDIENTS: Either in a bowl of a stand mixer with the whisk attachment or a large bowl (and using a hand mixer) combine butter and 3/4 cup powdered sugar. Cream together until smooth and creamy, about 3-4 minutes. Add in the vanilla, salt, cornstarch, and chopped pecans. Beat until smooth and combined. Add in the flour and beat slowly until combined and smooth. Add in chocolate chips and mix until combined. It will seem sandy and crumbly at first; keep mixing, and it will come together. Once combined, do not overmix.
CHILL: Wrap the dough in plastic wrap and refrigerate for 1 to 2 hours to chill (at least 1 hour).
BAKE: After being chilled, measure out cookie dough using a 1-tablespoon measuring spoon (each ball should use exactly 1 tablespoon). If the dough gets too warm from being rolled or sitting in a warm kitchen, put it in the freezer for 10-15 minutes. Preheat the oven to 375 degrees F. Line a light-colored sheet pan with a Silpat liner (See Note 3). Bake for 7-11 minutes (mine always take 10 minutes). Remove from the oven, let stand on tray for 3-5 minutes and then transfer to a wire cooling rack. Let cool for 2-3 minutes.
POWDEREDSUGAR: Add powdered sugar to a bowl (I start with 1 cup, but you may need slightly more). Roll the warm cookie in the powdered sugar and then return to the wire cooling rack. Let cool a few more minutes and then roll in the powdered sugar again. STORAGE: Store in an airtight container at room temperature. Re-roll in additional powdered sugar as needed. Best enjoyed within 1-3 days.
Note 1: Butter: It's important to use really good quality butter, not margarine. Use unsalted butter so you can control the salt amount. Make sure the butter is at room temperature, not melted or softened. One cup is the equivalent of 16 tablespoons or 2 sticks.Note 2: Vanilla: I'll also occasionally use vanilla bean paste; 1 teaspoon of paste if using!Note 3: Silpat: I tested this recipe with no parchment paper, with parchment paper, and with a Silpat liner. The cookie bottoms turned out best every time with the Silpat liner. The darker the trays, the darker the bottoms of the cookies. The best results I found were with a light-colored tray.Nutrition information includes 1 1/2 cups of powdered sugar used for coating the baked cookies. You may not use all of the sugar, and that will affect the final nutrition information.