Preheat oven to 350F. Add oats to blender and blend until you reach a flour-like consistency (read above for instructions if you do not have a blender).
Add in all ingredients except carrots, raisins, and walnuts and blend again
Stir in carrots, raisins, and walnuts.
Transfer batter to muffin tin and smooth out the tops with a spoon.
Bake 30-35 min at 350F.
Microwave all icing ingredients in a bowl for 15 seconds, stir, and spread onto muffins!