Mash one banana in a medium mixing bowl. Add milk, egg and vanilla. Whisk to combine.
Add 1 teaspoon of lemon zest and juice of half the lemon. Mix well.
Add the flour, protein powder, chia seeds, and baking powder. Mix together (batter may be lumpy).
Heat a large skillet over medium and add coconut oil (adding more if needed). Once hot, add 1/4 cup of batter to skillet, per pancake. Cook until bubbly and flip. Cook 1-2 minutes longer or until golden brown. Continue until all batter has been used.
Serve with maple syrup and the remaining bananas, sliced.