Bring butter and eggs to room temperature.

Preheat oven to 350 degrees Fahrenheit.

Grease and flour a tube pan.

In a large mixing bowl, beat butter and sugar until light and creamy.

Add eggs one at a time, beating until fluffy.

Stir in vanilla extract.

Mash bananas until smooth.

Add mashed bananas to the butter and sugar mixture and combine well.

In a separate bowl, sift together flour, salt, baking soda, and baking powder.

Gradually add the dry ingredients to the wet ingredients, alternating with buttermilk, beginning and ending with the dry ingredients. Mix until just combined.

Fold in the coarsely chopped walnuts.

Pour the batter into the prepared tube pan.

Bake for 40-60 minutes, or until a wooden skewer inserted into the center comes out clean.

Let the cake cool in the pan for 10 minutes before inverting it onto a wire rack to cool completely.

Frost with lemon cream cheese frosting (optional).