Preheat the oven to 350° F.
Place 2 cups of rolled oats in a blender jar and blend until the oats become a flour. Set aside.
In a small cup or bowl, mix the ground flax with the water. Set aside for 2 minutes to rest.
Place the mashed bananas, molasses, and brown sugar in a large mixing bowl. Mix together with a large spoon or rubber spatula.
Add the flax mixture and the vinegar. Stir again.
To the wet ingredients, add the blended and unblended oats, soda, baking powder, and the spices. Stir to incorporate.
Oil an 8x8 baking dish or round cake pan.
Spread the batter in the pan.
Bake for 30 minutes or until a toothpick stuck into the cake comes out clean.
Serve with Vanilla Sauce and optional whipped topping or ice cream.
Place the cornstarch in a small saucepan.
Whisk in the maple syrup and water.
Boil over medium-high heat for 1 minute or until slightly thickened.
Remove from the heat and stir in butter and vanilla.
Serve warm over the gingerbread cake.
Instead of the flax and water, a powdered vegan egg replacer can be used in the same quantity:1 tablespoon of the egg replacer powder plus 2 tablespoons of water mixed together.
Use any leftover sauce over pancakes or waffles or as a sauce on other cakes in place of frosting.