Preheat oven to 350 degrees and grease a 9 x 5 loaf pan with softened margarine. Place cubed bread in a large bowl.
In a small bowl whisk together ½ cup soy milk and the cornstarch until no lumps remain. Add 1½ cups soy milk, maple syrup, vanilla, and pumpkin pie spice and whisk to combine. Pour over cubed bread and stir to coat every piece. Allow to sit for at least 15 minutes for liquid to soak into bread. Mixture will be mushy and wet.
Mash together bananas and pumpkin. Fold mixture into the soggy bread. Pour mixture into loaf pan, patting down to make an even top.
Sprinkle brown sugar on top. Bake 30 minutes till top is slightly browned. Allow to cool slightly before serving. If you're eating this later on, warm in a 200 degree oven until ready to serve.
Source: Janel Ovrut MS, RD, LDN at www.eatwellwithjanel.com