Preheat the oven to 350°F. With a spoon, mix butter into the mashed bananas in a large mixing bowl. Mix in the milk, sugar, egg, honey, and vanilla. Sprinkle the baking soda and salt over the mixture and mix in. Add the flour last, mix. Pour mixture into a greased 4x8 inch loaf pan. Bake for 1 hour. Let cool, remove from pan, and slice to serve.