Add protein and coconut flour. Mix as much as you can with a fork or spoon, and then use your hands to fully combine the dough.
Place on a sheet of parchment paper and form into a rectangle.
Wrap the parchment around the dough and refrigerate for a couple of hours until firm.
Cut into 4 bars.
Mix icing ingredients, and pipe or drizzle over bars.
Enjoy! Store extras in the refrigerator.
Notes
Erythritol is a calorie-free natural sweetener, and is not included in the carb count here. Including the carbs adds 7.5g per bar but does not change the calories.If you'd like to substitute the whey with pea protein or casein, you'll need to add some liquid.