Preheat the oven to 160°C. Line a medium loaf tin with parchment paper or basket.
Beat the oil and sugar together until well combined. Add the eggs and vanilla, then the mashed bananas and mix until smooth.
Sift the flour, cinnamon and baking powder in a mixing bowl and combine.
Add the flour mixture to the egg mixture, then pour in the freshly made coffee. Combine gently, then fold in the chopped walnuts.
Transfer the batter into the prepared loaf tin and bake in the middle of the oven for about an hour or until a toothpick inserted into the centre comes out clean. You might have to cover the tin with foil, if the top of the loaf gets brown too soon.
Cool the banana bread for 10 minutes in the pan, then transfer it to a cooling rack.
When cooled, you can spread buttercream, cream cheese frosting on top or drizzle some icing over it, if preferred.