4 tbsp. Butter, cut into small cubes
1/4 tsp. Ground cinnamon
1/4 tsp. Kosher salt
1/2 cup Brown sugar
1/2 cup All-purpose flour
3 Ripe bananas, mashed
1/2 tsp. Espresso powder
1 tsp. Pure vanilla extract
1/4 cup Sour cream
1 Large egg plus egg yolk
1/4 cup Brown sugar
3/4 cup Granulated sugar
1/2 cup Unsalted butter, melted
1/2 tsp. Kosher salt
1 tsp. Baking soda
2 cups All-purpose flour
Cooking spray, for pan