Preheat oven to 180°C (350°F) conventional bake. Grease and line a 26cm (10-inch) loaf tin with baking paper.
In a large mixing bowl, mash the very ripe bananas using a fork until smooth with some small lumps remaining.
Add the melted butter, beaten eggs, sugar, and vanilla extract to the mashed bananas. Whisk together until well combined.
In a separate bowl, sift together the flour, baking soda, and salt.
Add the dry ingredients to the wet banana mixture. Stir gently until just combined - do not overmix. The batter should be slightly lumpy.
If using milk, fold it in gently at this stage for extra moisture.
Pour the batter into the prepared loaf tin and smooth the top with a spatula.
Bake for 45-55 minutes, or until the top is golden brown and a toothpick or skewer inserted into the center comes out clean.
Remove from oven and let cool in the tin for 10 minutes.
Turn out onto a wire cooling rack and allow to cool completely before slicing.
Serve sliced with butter, or store in an airtight container at room temperature for up to 5 days.
