Hummingbird cake is a banana pineapple spice cake common in the Southern United States. Ingredients include flour, sugar, salt, ripe banana, pineapple, cinnamon, pecans, vanilla extract, eggs, and leavening agent.ummingbird cake is a banana pineapple spice cake common in the Southern United States. Ingredients include flour, sugar, salt, ripe banana, pineapple, cinnamon, pecans, vanilla extract, eggs, and leavening agent.