Beat Becel® salted margarine sticks in large bowl with electric mixer until fluffy, about 3 minutes. Beat in sugar and vanilla until pale and fluffy, scraping down sides of bowl occasionally, about 2 minutes. Beat in flour on low speed just until blended.
Evenly press dough into 13- x 9-in. (33 x 23 cm) baking pan.
Bake 25 minutes or until firm and golden. Cool 15 minutes on wire rack. Cut into 36 pieces, approximately 2-1/2 x 1-in. (6 x 2.5 cm). Remove from pan and cool completely.