Preheat oven to 350 degrees F (175 degrees C). Grease a muffin tin with butter.
Combine flaxseed meal, sugar, chia seeds, baking powder, and cinnamon in a bowl. Add bananas, eggs, and apple; mix batter thoroughly. Stir in 6 tablespoons coconut flakes. Fill tin 3/4 full with batter. Sprinkle remaining 2 tablespoons coconut flakes on top.
Bake in the preheated oven until tops spring back when lightly pressed, about 30 minutes.