Preheat oven to 180 degrees C. Grease a 20x30cm baking dish.
Beat the margarine, cream cheese and sugar with an electric mixer in a large bowl until smooth. Add the eggs one at a time, allowing each egg to blend into the margarine mixture before adding the next. Beat in the vanilla with the last egg. Mix in the flour, salt, chocolate chips and walnuts until just incorporated. Fold in the maraschino cherries; mixing just enough to evenly combine. Spread the batter evenly in the prepared pan.
Bake in the preheated oven until a skewer inserted in the centre comes out nearly clean, about 25 minutes. Watch closely - the finished bars will be very pale in colour. Remove from oven immediately if the sides begin to pull away from the pan. Cool pan on a wire rack before cutting into bars.