Preheat oven to 350°F. Toast pecans in single layer on baking sheet for 8 to 10 minutes. Set aside to cool.
Beat butter in large bowl using electric mixer for 1 minute or until smooth and creamy. Add granulated sugar and brown sugar. Beat on high speed until light and fluffy.
Add eggs and vanilla; beat on high speed until light and fluffy.
Sift in baking soda and salt; beat on high speed until well incorporated.
Add flour to butter/sugar mixture, and beat on low speed just until combined.
Stir in the toasted chopped pecans until evenly disbursed.
Cover dough with plastic wrap or aluminum foil, and chill for at least 3 hours and up to 3 days. Do not skip this step.
Preheat oven to 350°F.
Line two large baking sheets with parchment paper or silicone baking mats.
Remove cookie dough from the refrigerator. Scoop and roll balls of dough, about 1-½ Tablespoons of dough each, into balls.
Bake the cookies for 10 minutes (11 minutes for crispier cookies), until slightly golden brown around the edges. The baked cookies will look extremely soft in the centers when you remove them from the oven. Allow to cool for 5 minutes on the cookie sheet. If the cookies are too puffy, gently press to flatten. Transfer to a wire rack to cool completely.
Yield: 3 dozen cookies.
Note: Cookies will stay fresh in an airtight container at room temperature for several days. Unbaked cookie dough balls freeze well for up to three months. Bake frozen cookie dough balls for an extra minute, no need to thaw.