Reserve 1/2 cup pecan pieces; place remaining pecan pieces in food processor; pulse until finely chopped. In medium bowl, combine finely chopped pecan pieces, flour and salt; set aside.
In large bowl, cream butter, granulated sugar and syrup using electric mixer. Add egg yolk and maple extract, mix well. Gradually add flour mixture, mixing until just combined. Shape dough into disk; wrap in plastic wrap. Refrigerate 2 to 3 hours.
Preheat oven to 350ºF. Coarsely chop remaining 1/2 cup pecan pieces. Line 2 baking sheets with parchment paper. On lightly floured surface, roll out dough to 1/4-inch thickness. Cut out rounds using 2-inch round cookie cutter; place rounds on prepared baking sheets spacing 1-inch apart. Sprinkle pecan pieces over rounds; gently press pieces into rounds. Brush tops with beaten egg. Sprinkle cookies with turbinado sugar.
Bake 12 to 15 minutes or until golden brown. Cool cookies on baking sheets 3 minutes; transfer to cooling rack. Cool completely.
