In this photo from the web, the plantains are on the far left, and varieties of bananas are on the right.
In another photo from the web, you can see how a plantain looks as it ripens. When it is really, dark, it's ripe. Ripe plantains are sweeter than green plantains, but not nearly as sweet as a banana. You wouldn't want to eat one raw. They are difficult to peel and it pretty much requires a knife, as the skin is so thick and tough.
This recipe is from www.dollarman.com. The original recipe is called a bread, but I found it sweet and dense, like a cake. I decided to frost it with a simple cream cheese frosting.
1 cup mashed ripe plantain
1/2 cup margarine
1 1/4 cups flour
1 1/2 cups sugar
1 teaspoon baking soda
4 tablespoons sour cream
1 teaspoon vanilla
1 teaspoon baking powder
Beat margarine until soft; add sugar, eggs, and sour cream.
Blend plantains, flour, baking soda, and baking powder. Add to the previous mixture. Add vanilla and beat thoroughly.
Pour mixture into a greased and floured 8x8-inch pan. Bake in a preheated 350F oven for about an hour. Check with a toothpick to ensure that the cake is cooked.
After the cake was cooled, I made a quick frosting of 1/2 stick butter, about 4 ounces of cream cheese, and powdered sugar to taste. Just mix everything well.
This will not taste like a banana cake. Similar, but not the same. I like that taste, and Dave enjoyed it. It is a bit unusual though.