3 cups all-purpose flour
1 1/2 teaspoons baking soda
3/4 cup (1 1/2 sticks) butter, at room temperature
2 1/4 cups granulated sugar
3 eggs, well beaten
5 ripe bananas, mashed
1/4 cup buttermilk
1 1/2 teaspoons vanilla extract
1 cup finely chopped pecans

Preheat oven to 325 degrees F. Grease and flour three 9-inch cake pans. Sift together flour and baking soda, and set aside.

Put butter and sugar in a large mixing bowl and cream together until smooth. Slowly pour in the eggs, mixing well between each addition. Stir in the mashed bananas. Add dry ingredients and buttermilk alternately, beginning and ending with flour mixture. Stir in vanilla extract and pecans. Divide batter among prepared pans and bake for 25 minutes, or until the tops all brown and the edges pull away from the pans, or a wooden pick inserted in the middle of a cake comes out clean. Remove from the oven and allow to cool for 5 to 10 minutes, then turn out onto racks to cool completely.

Frosting and Filling
1/2 cup mashed bananas
2 teaspoons fresh lemon juice
1/2 cup (1 stick) butter, at room temperature
1 pound confectioners sugar
1 teaspoon vanilla extract
3 ripe bananas, sliced thin

In a small bowl, mix mashed bananas and lemon juice together and set aside.

In another bowl, with an electric mixer, cream together butter and sugar. Add mashed bananas, blending well. Stir in vanilla extract.

To assemble, spread a layer of icing on one of the cake rounds, then top with a layer of sliced bananas. Place the second cake layer on top of the bananas and repeat with more icing, then bananas. After placing the third layer on top, smooth the icing over the sides and top of the cake with the remaining frosting.