- 1 cup pecans, toasted
- 1 cup (2 sticks) unsalted butter, room temperature, divided
- 2 cups sifted all purpose flour
- 1/4 teaspoon coarse kosher salt
- 1/2 cup sugar
- 1 teaspoon vanilla extract
- Grind pecans in processor until coarse meal forms. Melt 1/2 cup butter in small skillet over medium heat. Cook until dark amber, stirring often, about 6 minutes (do not burn). Pour through fine strainer into small bowl. Chill just until firm, about 1 hour.
- Preheat oven to 300°F. Whisk flour and salt to blend. Using electric mixer, beat brown butter, 1/2 cup butter, and sugar in large bowl until creamy. Beat in vanilla, then nuts. Gradually beat in flour mixture on low speed just to blend.
- Transfer dough to sheet of parchment paper. Form dough into rectangle. Place second sheet of parchment paper over dough. Press or roll dough into 12×8- inch rectangle. Remove top sheet of parchment. Transfer dough on parchment to baking sheet. Using fork, pierce dough all over, spacing 1 inch apart.
- Bake shortbread until golden brown and firm to touch, about 55 minutes. Leaving shortbread on baking sheet, cut lengthwise into 8 strips. Cut each strip crosswise into quarters. Cool 10 minutes on sheet on rack. Transfer cookies to rack to cool completely. DO AHEAD: Can be made 3 days ahead. Store airtight at room temperature.