Stir together first 7 ingredients in a heavy skillet over medium heat, stirring until butter melts and sugar dissolves. Remove skillet from heat; add nuts, and toss to coat.
Place pecan mixture in a single layer in an aluminum foil-lined 15- x 10-inch jellyroll pan.
Bake at 250° for 1 hour, stirring every 15 minutes. Cool in pan on a wire rack, separating pecans with a fork. Store in an airtight container up to 1 week, or freeze up to 1 month.