Blend margarine and shortening until creamy. Add powdered sugar; mix well. Add flour; mix well.
Press dough evenly in bottom of ungreased 9x13 inch pan about 1/2 inch up sides. Bake in preheated 350F oven for 12-15 minutes or until light brown.
In medium bowl, stir filling ingredients together very gently with fork. Do not beat; just stir gently until well mixed. Pour filling over hot crust and spread evenly. Bake for 20 minutes. Cool; cut into 1x3 inch bars.
Cajun Country -- New Iberia, Louisiana