Spread the pecans out on a heavy baking sheet and toast at 400 degrees for 6 to 8 minutes, watching carefully, so that they don't burn. Cool them completely, then chop coarsely.

Brown the butter in a 3 quart sauce pan, over a medium flame. Stir and swirl the pan to keep it from browning unevenly. It will foam up, and you will begin to see browning in the center of the pan first. It should have a pleasant, nutty sort of aroma and the color should be quite dark, but not blackened at all. Scrape the butter into your mixing bowl, and cool to room temperature.

Cream the butter briefly, then cream in the sugars, beating until somewhat fluffy - a minute or so.

Beat in the eggs, one at a time, and then the vanilla.

Add the dry ingredients, and beat until completely incorporated.

Beat in the pecans.

Scrape the dough into a smaller bowl, or onto a sheet of plastic wrap, and chill completely. If you can wait, it is best after about 24 hours.

When the dough is chilled, preheat the oven to 350º, and line heavy baking sheets with parchment paper.

Portion the dough with a medium cookie scoop, and place on the sheets, round side up.

Bake for about 14 minutes, turning sheets halfway through.

Cool on the parchment for a couple minutes, then move to a rack to finish cooling.

Store tightly covered at room temperature for up to a week.