Preheat oven to 350 degrees F. Line two 9x13-inch trays with silicone mats.

Add pecans to small bowl and toss with maple syrup. Arrange on prepared tray. Roast for 12-14 minutes, stirring periodically, until caramelized and fragrant. Set aside to cool.

Combine sugar, butter, water, corn syrup and salt in large, heavy-bottomed stock pot. Bring to boil over medium heat, stirring until butter melts and sugar dissolves. Brush sides of pan with wet pastry brush.

Reduce heat to low. Cook uncovered, stirring just once halfway through, until mixture reaches 290 degrees F on candy thermometer, about 15 minutes.

Remove from heat. Pour onto second prepared tray. Cool 5 minutes.

Scatter toffee with grated chocolate. Allow chocolate to melt 2 minutes, then spread with rubber spatula. Press maple-glazed pecans into melted chocolate.

Refrigerate until chocolate sets. Break toffee into pieces. Store in airtight container in cool, dry place for up to 1 week.