Wet batter under banana decoration in bread?

It's nice to put something on top of a loaf cake as both garnish and a sign of the main flavor.
One way to do this is to stud a cream cheese frosting with candies indicating the main ingredient...e.g., banana chips, marzipan carrot or apple.
Looks pretty and no problem with unbaked cake.

I know this is an old post, but in case you're still looking for a trusted recipe that incorporates a sliced banana as decoration on top, try this: https://www.splendidtable.org/recipes/cocoa-banana-bread. In the recipe notes, it says that the top will sink a little due to the weight of the banana. And the comments have some helpful tweaks.

Tartan's banana-date tea cake has you put halved bananas on top before cooking and I've wound up with underdone batter underneath. I honestly think it just has to do with how much liquid your bananas give off during baking/how much liquid is in the recipe. Its just a balance. My problem is, if you just continue to bake the cake, the ends come out quite overbaked while you're waiting for the middle to be done. The best remedy I've seen for this comes from Cook's Illustrated. They slice the banana into coins and shingle it along the sides of the cake. That allows the batter to convect and bake fully in the center while protecting the sides. It's not quite as beautiful as the interlocking banana halves, but it works.

I personally haven't done the banana slices on top before, but I asked the rest of our team, and those who have just baked it slightly longer.