Preheat oven to 375 degrees. Grease and flour a 9-inch round baking pan.
In a large mixing bowl, stir together the melted butter, sugar and bananas. Add the vanilla extract, baking soda and salt and stir well to combine. Add the flour and stir well. Pour into the baking pan.
Bake for 40-50 minutes, until a cake tester inserted in the middle comes out clean.
Cool completely. If desired, frost before serving.
Recipe by Sarah's Cucina Bella at http://sarahscucinabella.com/2015/05/06/easy-banana-cake/