Preheat the oven to 350°F. Grease and flour a 9x13-inch baking pan.
In a large bowl, mix together the cake mix, eggs, oil, and water. Beat until combined. Pour the batter into the prepared pan and bake for 25-30 minutes, or until a toothpick inserted into the center comes out clean.
Meanwhile, make the custard. In a medium saucepan, combine the sugar, cornstarch, and salt. Gradually whisk in the milk and cook over medium heat, stirring constantly, until the mixture thickens and boils. Boil for one minute, then remove from the heat and stir in the vanilla and almond extracts.
When the cake is done baking, let it cool completely. Once cooled, make the whipped cream. In a medium bowl, beat the heavy cream and powdered sugar until soft peaks form. Spread the custard over the cake, then spread the whipped cream and sprinkle with the walnuts and cherries.
Slice and serve.
Interesting Facts
Bananas are native to Southeast Asia but are now grown in many tropical regions around the world.
The custard in this recipe is similar to pastry cream, which is a common filling for cakes and other desserts.
This cake is a great way to use up overripe bananas.