Ingredients: Cake: Nonstick cooking spray, for the pan Two 14-ounce boxes banana quick bread mix Filling: 4 tablespoons (1/2 stick) unsalted butter 1/3 cup packed light brown sugar 1/3 cup maple syrup 2 teaspoons vanilla 1/2 teaspoon ground cinnamon Pinch of kosher salt 1/2 cup …