Preheat oven to 350 F and grease 36 mini muffin tins.
To a bowl, mix together the banana, peanut butter, eggs, vanilla, butter and cherries. To another large bowl, mix the flour, powdered peanut butter, baking powder, cinnamon and flax. Add the wet ingredients to the dry and mix until combined.
Add the batter to the muffin tins (pretty much up to the top) and sprinkle with hemp hearts. Bake for 10-12 minutes until a toothpick inserted into the middle comes out clean and the muffins feel springy.