Add in the mashed banana, peanut butter and mint leaves if desired.
Mix all the ingredients until they are well combined.
Pour the mixture - or the melted coconut oil by itself - into small silicone containers. Try using shaped containers for holiday treats.
Freeze the filled containers until the shapes are solid.
Pop the frozen treats out and place them in a Ziplock back quickly, then put them back into the freezer. These do melt fast once they are exposed to room temperature, so work quickly.
Place a single treat on top of your dogs food once or twice per day.