Have you heard of bananas foster? Butter and sugar are roasted in a pan, then sliced bananas are added until they start to soften. At the very end, some rum is sploshed in, before the whole mixture is spooned over ice cream while still warm.
The same concept is applied to this (relatively healthy) banana bread. The bananas are roasted with butter and sugar until they caramelize a little, and then the mixture is mashed together until everything is homogenous.
That sweet sticky mixture is incorporated into the rest of the ingredients, and baked in a loaf pan till golden. Afterwards, a thick glaze is spooned over the entire loaf, so that it dribbles into every crevice.

