Bananas Foster is a dessert dish created by executive chef Paul Blangé in 1951 at Brennan's -- a well-known creole restaurant in New Orleans's French Quarter. Traditionally, the dish involves caramelizing brown sugar and cinnamon in butter along with bananas and banana liquor, and then flambéing it with dark rum. It's typically served over vanilla ice cream. If you don't have dark rum, or simply do not want to use it, there are a few substitutions you can consider that will give you good, albeit somewhat different, results.
Cachaca, the national spirit of Brazil, is a liquor made from sugarcane juice. It has some similarities to rum, but rums are typically made from molasses instead of straight sugarcane juice. Like rum, cachaca can be white or dark -- the dark version is normally aged in oak barrels. Dark, aged cachaca can take on a number of flavor notes from the barrel including dried or roasted fruit, sweet spice, coffee, herbal or grassy notes. Though there are some distinguishable flavor differences, dark cachaca does makes a flavorful and interesting substitute for dark rum in Bananas Foster.
Possessing many of the same sweet, woody flavors of many dark rums, bourbon works very well with no modifications or additions in most Bananas Foster recipes. In fact, some Bananas Foster recipes actually call for bourbon instead of dark rum.
Brandy is often used in other flambéed desserts similar to Bananas Foster such as Cherries Jubilee. However, brandy typically lacks the underlying molasses flavors indicative of most dark rums. To make up for this when using brandy in Bananas Foster, add a small amount of molasses to the sugar and cinnamon in your Bananas Foster recipe.
You can also use rum extract as a substitute for dark rum. You can substitute 1.5 teaspoons of imitation rum extract per tablespoon of dark rum in your Bananas Foster recipe. However, keep in mind that if you are making this substitution because you are trying to avoid alcohol, rum extract is not always alcohol free. Read the label to determine if it contains alcohol. Also, due to the low amount, or complete lack of, alcohol in rum extract, you will not be able to flambé your Bananas Foster. Finally, for better flavor, try to use real versus imitation rum extract, as the flavor has more depth and less of a "chemical" taste.
As non-alcohol alternatives that you also can't flambe, you can substitute grape juice, pineapple juice or apple juice on a 1-to-1 basis for dark rum in most recipes -- including Bananas Foster. To more closely approximate the flavor of dark rum, add a small amount of almond and vanilla extract to your juice before using it in your recipe.