Beat margarine and sugar until light and fluffy. Blend in egg and vanilla. Add combined dry ingredients; mix well. Spread mixture evenly onto bottom and 1-inch up sides of 9-inch springform pan. Combine cream cheese, topping and half and half, mixing at medium speed on electric mixer until well blended. Add eggs, one at a time, mixing well after each addition. Blend chocolate into 1 cup cream cheese mixture. Pour remaining cream cheese mixture over crust. Spoon chocolate batter over cream cheese mixture; cut through batter with knife several times for marble effect. Bake at 425F for 10 minutes. Reduce oven temperature to 250F. Continue baking 45 minutes. Loosen cake from rim of pan; cool before removing rim of pan. Chill.
Makes 10 to 12 servings.
Cajun Country -- New Iberia, Louisiana