Combine the tofu, brown rice syrup, and Sucanat in a small saucepan. Heat for about 5 minutes over medium heat, stirring constantly. Then pour the mixture into a blender and blend until smooth. Transfer to a mixing bowl. Add the peanut butter and margarine and beat until smooth. Refrigerate the icing for 1 hour, or until firm.

This recipe will be sufficient to cover a large two-layer cake.