Blend oats into a fine flour using a food processor or blender.
In a large bowl, mix oat flour, protein powder, almond flour, cinnamon, and salt.
Add almond butter, honey, and vanilla. Stir well. If it's too dry, add almond milk one tablespoon at a time until a dough forms.
Press into a parchment-lined loaf pan or baking dish.
Mix icing ingredients in a small bowl and spread over bars.
Chill in the fridge for at least 1 hour, then slice into bars and enjoy.
