Start by peeling the bananas, cut them into small round slices and put them into a blender.
Add the milk and the eggs, blend very well.
Add the corn starch, blend again and set aside.
Into a skillet, add the sugar and stir until melted, when that happens, keep gradually adding some water and stir until a caramel sauce is formed.
Once you’ve done that, transfer all the caramel sauce to an 18cm-diameter aluminum ring cake mold. Spread the caramel sauce all over the mold and pour in all the flan batter.
Place the cake mold into a large pan filled with hot water, let it cook for 40 minutes in a double boiler.
I’m using a special mold for this process, but you can use a regular one and cover the flan with aluminum foil instead.
After this indicated time, the flan has baked through.
You may remove it from the heat, wait until it cools and unmold it.
Serve.