Heat your oven to 350°F and grease a 9X5-inch loaf pan.
In a medium-large mixing bowl, stir the mashed bananas together with the egg, sour cream, espresso, and vanilla extract, until everything is well combined.
Stir in the instant espresso granules.
Next, stir in the melted oil/butter until it is completely incorporated.
Follow this by stirring in the sugar until everything is well mixed.
In a small bowl, stir together the flour, baking soda, and salt.
Dump this mixture into the wet ingredients and stir just until there are no dry streaks left. The batter will still be lumpy.
Scrape the batter into the prepared loaf pan and bake in the oven until a tester inserted into the loaf comes out clean, about one hour.
Remove from the oven, allow to cool in the loaf pan for 10 to 15 minutes, then gently run a knife around the edge of the bread and turn it out of the pan.
Finish cooling the bread on a cooling rack.
