2 to 3 medium (7" to 7-7/8" long) very ripe bananas, peeled (about 1 1/4 to 1 1/2 cups mashed)
1/3 cup (76g) butter, unsalted or salted, melted
1/2 teaspoon baking soda (not baking powder)
1 pinch salt
3/4 cup (150g) sugar (1/2 cup if you would like it less sweet, 1 cup if more sweet)
1 large egg, beaten
1 teaspoon vanilla extract
1 1/2 cups (205g) all-purpose flour