1. Cook butter in a small heavy saucepan over medium heat, stirring constantly, 6 to 8 minutes or until butter begins to turn golden brown. Remove pan from heat immediately, and pour butter into a small bowl. Cover and chill 1 hour or until butter is cool and begins to solidify.
2. Beat butter at medium speed with an electric mixer until creamy. Gradually add brown sugar and powdered sugar, beating until smooth. Gradually add flour to butter mixture, beating at low speed just until blended. Stir in pecans.
3. Shape dough into 4 (8-inch) logs. Wrap logs tightly in plastic wrap, and chill 4 hours or until firm.
4. Cut logs into 1/4-inch-thick rounds; place on lightly greased baking sheets.
5. Bake at 350° for 8 to 10 minutes or until lightly browned. Transfer to wire racks to cool.
Bake time is per batch.