Preheat oven to 350 degrees F (175 degrees C). Coat the inside of a 9x13-inch baking dish with cooking spray.
Combine cornmeal, flour, baking powder, cinnamon, and allspice together in a bowl.
Whisk soy milk, sour cream, pumpkin, oil, agave nectar, and egg together in a bowl until smooth. Mix cornmeal mixture into soy milk mixture until batter is smooth; pour into the prepared dish.
Bake in the preheated oven until the top springs back when gently touched and edges are brown, 25 to 30 minutes.
