Preheat oven to 275°F and grease and flour a 9x13-inch metal cake pan.
On a dinner plate place the peeled bananas and use a fork to mash them.
Then place bananas in a bowl and pour lemon juice on top; set aside.
In a medium bowl, mix flour, baking soda, and salt; set aside.
In a large bowl, cream ¾ cup butter and sugar until light and fluffy.
Beat in eggs, one at a time.
Then stir in the vanilla extract.
Beat in the flour mixture alternately with the buttermilk.
Stir in banana mixture.
Pour batter into prepared pan and bake in preheated oven for 1 hour or until a toothpick inserted in center comes out clean.
Remove from oven and place directly into the freezer for 45 minutes.