Line a 9-by-13-inch glass pan with parchment, letting it hang over the sides. Set aside. Combine the peanut butter, honey and chocolate milk in a medium heatproof glass bowl and place over a pot of simmering water. Allow the mixture to become warm and smooth, stirring to completely incorporate. Remove from the heat and set aside. Meanwhile, mix the oats, flax seeds, protein powder, dried cherries and half of the chocolate chips in a large bowl.
4. Pour the peanut butter mixture into the oat mixture and stir until well combined. Transfer the mix to the prepared pan and press the mixture into an even layer. Sprinkle over the remaining chocolate chips, lightly pressing them into the base, and freeze for 15 minutes to allow the mixture to set. Remove from the pan and cut into 24 bars, then transfer to an airtight container and freeze. When ready to eat, remove from the freezer and allow to thaw slightly, 2 to 3 minutes, before enjoying.