Cake Batter: Cream butter and sugars. Add eggs and sour cream (room temp ideal!). Add mashed banana and vanilla. Combine dry ingredients in a separate bowl. Add dry to wet and mix till just combined.
Caramel Filling: Cook butter and brown sugar till dissolved. Add cream and simmer for 2-3 min. Add salt, vanilla and cinnamon. Add bananas and continue to cook till thick (2-3 min).
Streusel Topping: Mix together with your hands till large clumps form. Chill while making your caramel and cake batter.
In an 8x8 pan, layer ½ cake batter, banana caramel, cinnamon sugar (~½ cup brown sugar w 1 tbs cinnamon!), other ½ cake batter, streusel, then caramel drizzle.
Bake at 350F for 45 min to an hour, till a toothpick comes out clean.
Tent with foil if the top starts to get too dark!
