Preheat the oven to 350 F (180 C),
Line a 12-muffin tin with paper liners.

In a bowl, mix the banana slices with the lemon juice. Mix to coat the slices well and set aside.

In a bowl, combine the flour, baking powder, brown sugar, coconut, and pinch of salt.
In another bowl, dissolve the coffee in the lukewarm milk, then add the melted butter and eggs and mix well.

Add the bananas to the dry ingredients and mix to coat well, so the bananas don’t sink to the bottom of the muffins during baking.
Add the wet ingredients and mix with a fork, just until the dry ingredients are no longer visible.

Divide the preparation into the muffin tin, then bake for 20 minutes or until a toothpick inserted into the center comes out clean.
Remove from the oven, let rest for 5 minutes before transferring the muffins to a cooling rack.