Preheat the oven to 350°F
In a large mixing bowl, (with a wooden spoon) mix butter into the mashed bananas .
Mix in the sugar, egg, and vanilla.
Sprinkle the baking soda and salt over the mixture and mix in.
Add the flour last, then mix.
Lightly mix in most of the nuts after all ingredients mixed well.
Pour mixture into a buttered (or spray with Pam) mini muffin pan.
Top with additional nuts.
Bake for 20-22 mins
Cool on a rack (in the pan).
Remove from pan and slice to serve!