Monkeys young and old will love this mash-up of banana split, ice cream cake and sundae. Make sure to cook the butter in the cake to a deep brown-it should smell very toasty when it’s done, and it will give the cake a rich, nutty flavor. You can make the chocolate sauce a few hours ahead of time and hold it at room temperature.
Banana Ice Cream Cake
Preheat the oven to 350ºF. Butter a 9-by-13-inch baking pan.
Melt the butter in a medium skillet over medium heat until nutty brown. Immediately remove from the heat and reserve.
Whisk the flour with the baking soda and salt in a medium bowl. Vigorously whisk the bananas with the browned butter in a large bowl until very well combined and creamy. Whisk the egg, brown sugar, granulated sugar and vanilla into the banana mixture until smooth.
Fold the flour mixture into the banana mixture with a rubber spatula until well combined. Pour the batter into the prepared pan and spread to cover completely; the layer will be thin. Bake until a toothpick inserted in the center comes out clean, about 18 minutes. Cool completely on a rack, about 1 hour.
Spread the ice cream evenly over the banana cake with a rubber spatula. Cover with plastic wrap and freeze until firm, at least 4 hours or overnight.
Combine the chocolate, cream, corn syrup, butter and salt in a medium saucepan over medium heat. Whisk periodically as the mixture comes to a gentle simmer. Simmer for 5 minutes, stirring occasionally. If the sauce starts to boil, turn down the heat. Cool 15 minutes before serving. Transfer to a bowl or small pitcher. (Yield: 1 2/3 cups.)
Remove the cake from the freezer and let stand at room temperature. Heat a large skillet over medium heat. Add the butter and swirl the pan. When the butter is completely melted, place the banana pieces cut-sides down in one layer in the pan. When they are nicely browned, after 4 to 5 minutes, flip the bananas. Cook until the other sides are browned and the bananas have softened, 2 to 3 minutes. Transfer to a bowl.
To serve, place desired toppings in bowls. Cut squares of the banana cake and divide among serving bowls. Let each person build a sundae with the chocolate sauce, caramelized bananas, and additional toppings.