Preheat oven to 350°F. Butter and flour a 12-cup fluted bundt pan or spray the pan with nonstick cooking spray with flour.
Whisk together flour, salt, and baking soda in a medium bowl.
Mash your bananas with a fork.
With an electric mixer, cream butter and both sugars until light and fluffy. Stir in mashed bananas and vanilla. Add eggs, one at a time, beating well after each addition.
Mix in the sour cream and the flour mixture. Beat the mixture until it just comes together.
Pour batter into prepared pan. Bake for about 50-60 minutes or until a toothpick comes out clean.
Once done, cool cake in pan for 20 minutes, then turn out onto serving platter. Cool compltely before frosting.
Make the frosting: Mix butter and cream cheese. Mix in powdered sugar, salt and vanilla. Spread over cake. Optional: top with chopped pecans or walnuts.
Store cake loosely covered in the refrigerator. It tastes best at room temperature. Will keep for up to 3 days.