Create your cinnamon roll topping by combining all ingredients into a small bowl & mixing well until a crumbly consistency forms. Set aside.
In a large bowl, combine your mashed banana, brown sugar, melted butter/oil, eggs, & vanilla. Mix well.
Fold in the flour, baking powder, & cinnamon into the batter. Mix until thoroughly combined.
Pour batter into a parchment paper lined 8x8 baking pan. Spoon cinnamon roll topping mixture over top of batter in an even layer. Bake @ 350 degrees for 30-33 minutes or until a toothpick inserted comes out clean.
Remove & let cool. While cake is cooling, prepare vanilla glaze by combining all ingredients into a small bowl. Drizzle glaze over top of cake, slice, & enjoy!