Pre-heat oven to 375F and line a jumbo muffin tray with parchment paper or muffin liners.

Melt the butter in a nonstick saucepan over medium-low heat until it turns brown and fragrant.

Add the brown butter to a bowl along with the brown sugar and whisk for 1-2 minutes.

Wait 3-5 minutes for the mixture to cool slightly, then add the eggs, vanilla, and instant coffee mixed with hot water. Whisk until smooth.

Add the mashed bananas and sour cream, whisk until combined.

Sift in the flour, baking powder, baking soda, and salt, then gently fold until just combined.

Fold in the chocolate chips.

Divide the batter evenly between the muffin cups and top with more chocolate chips if desired.

Bake for approximately 27-30 minutes until a toothpick inserted comes out with light, moist crumbs.

While the muffins bake, prepare the ganache by heating the cream until it just starts to boil, then pouring it over the chocolate in a bowl. Cover and let sit for 5 minutes, then stir until smooth.

Let the ganache cool to thicken, then fill each muffin with ganache using a piping bag.