Take a crack at this intensely rich and buttery holiday treat.
Line a 15- x 10-inch jelly-roll pan with parchment paper, and lightly coat with cooking spray.
Melt butter in a large heavy saucepan over medium heat; stir in granulated sugar, next 4 ingredients, and 1/3 cup water. Cook, stirring constantly, until a candy thermometer registers 290° (soft crack stage), about 17 to 20 minutes. Remove pan from heat, and stir in pecans. Immediately pour mixture into prepared pan. Spread in an even layer, and sprinkle bittersweet and semisweet chocolate morsels over top. Let stand 5 minutes. Spread and swirl chocolate using an offset spatula. Chill 1 hour or until firm. Break toffee into pieces. Store in an airtight container in refrigerator up to 7 days. Serve cold or at room temperature.