Spray 13x9-inch pan with cooking spray. Combine flour and sugar in a medium bowl. Cut in butter with pastry blender or 2 knives until mixture resembles coarse crumbs; press firmly into prepared pan. Bake 15 to 20 minutes or until the edges are just beginning to brown.
Filling: Melt butter and chocolate in large saucepan over low heat, stir until melted and smooth. Blend in corn syrup, sugar, eggs and vanilla with a wire whisk; pour over crust. Sprinkle with pecans and candies.
Bake 27 to 32 minutes or until filling is set. Refrigerate for 1 hour. Cut into 24 bars.
**Note: Instead of pecans halves, use a mixture of pecans, chopped walnuts and slivered almonds.