Preheat the oven to 350ºF (180ºC). Line the bottom of an 8-inch square cake pan with parchment paper. Grease and flour the insides.
In a medium-size bowl, whisk together the flour, cinnamon, baking soda, salt and nutmeg until well combined.
In a large bowl, beat the butter, with an electric mixer on medium speed, until light and creamy, Add the brown sugar and oil. Continue beating until creamy and well incorporated, about 2-3 minutes. Beat in the eggs and vanilla extract in 3 separate additions, making sure each one is incorporated before adding the next. Stir in the mashed bananas. Add the flour mixture in two additions, followed by half of the sour cream after each addition. Mix just until combined.
Transfer the batter to the prepared cake pan. Bake until a toothpick inserted into the center of the cake comes out clean, about 25-30 minutes. Let the cake cool in the pan for 10 minutes, then remove it from the pan and place it on a cooling rack.
Cream Cheese Frosting & Salted Caramel
In a medium-size bowl, stir the cream cheese with a spatula until smooth. Beat in the butter, with an electric mixer on low speed, until smooth and well combined.
Beat in the powdered sugar, vanilla, salt and heavy cream, on medium speed, until smooth and well combined. Stir slowly with a spatula to smooth the frosting and remove bubbles.
Spread the cream cheese frosting on the cooled cake. Drizzle with a couple of tablespoons of salted caramel sauce and swirl it into the frosting with a spoon, adding more if desired.
Recipe Notes
*For my homemade caramel sauce recipe, click here.