(Nutrition information is calculated using an ingredient database and should be considered an estimate.)
Preheat oven to 375°F (190°C). Combine flour, baking soda and salt in medium bowl; set aside.
Mix 1 cup (250 mL) Becel® Buttery Taste margarine with sugars in large bowl. Mix in eggs and vanilla until blended. Gradually add in flour mixture; mix just until blended. Finely chop 1/3 cup walnuts and stir in. Drop by tablespoonfuls on ungreased baking sheets, 2-in. (5 cm) apart.
Bake 7 minutes or until edges are golden. Cool cookies on sheets 2 minutes on wire rack; remove cookies from sheets and cool completely.
Combine remaining 2 Tbsp. margarine with milk in microwave-safe bowl and microwave until margarine is melted and mixture is hot, about 1 minute (timing will depend on the wattage of your microwave). Place chips in small bowl and pour hot milk mixture over chips. Let stand 5 minutes then stir until smooth. Place a dollop of chocolate ganache over centers of cookies, spread slightly and top with remaining walnut pieces.