Preheat the Oven: Preheat the oven to 350°F (175°C) and grease a loaf pan.
Mix Dry Ingredients: In a bowl, whisk together flour, baking soda, salt, cinnamon, and nutmeg.
Mash Bananas: Mash the bananas in a separate bowl.
Combine Wet Ingredients: Stir in melted butter, sugar, eggs, and vanilla into the mashed bananas.
Add Dry Ingredients: Gradually fold in the dry ingredients and sour cream.
Make Mocha Syrup: In a saucepan, combine brewed coffee, brown sugar, cocoa powder, and butter. Simmer for 5 minutes.
Assemble and Bake: Pour half of the batter into the pan, drizzle with mocha syrup, and top with the rest of the batter. Bake for 55-60 minutes.
Cool and Serve: Allow the bread to cool before slicing.