Preheat the oven to 400 and line a baking sheet with parchment paper or a reusable silpat.
Optionally pulse the oats in a food processor or blender about 10-15 times. Or if you like the heartier texture of the oats, skip this step.
In a bowl whisk together the flour, baking soda, kosher salt, cinnamon, and oats, set aside.
In a mixer cream the butter and sugar together on medium speed for 2 minutes.
Add the eggs and mix about 30 seconds.
Turn the speed to low and drizzle in the molasses. Tip: Turn the mixer off and scrape the sides down as necessary.
Add the flour/oat mixture a little at a time just until it is combined. Don't overmix at this point.
Using a cookie scoop, drop about 1.5 tablespoon of dough on the lined baking sheet.
Bake for 8-10 mins just until the edges are JUST starting to turn golden. Tip: If you are baking in batches, pop the rest of the dough in the fridge while the other cookies bake.
Cool on the baking sheet for about 4-5 minutes, then transfer to a cooling rack.
Cool completely before icing.
Icing
When the cookies are completely cool, it is time to add the icing! tip: place a used parchment paper sheet under the cookie cooking rack to catch icing drips, it will make for quicker clean up!
In a bowl whisk or stir the powdered sugar, milk and vanilla together. It will be a VERY thick icing. If all the powdered sugar won't mix in add a drop or two of milk until it comes together. tip: Choose a shallow bowl that you can dip the cookies into.
To get the crackly icing look- very lightly and quickly dip the top of the cookie into the icing. Let the excess icing drain off the cookie, you can shake it a little to speed up the process. tip: if you are heavy handed with the icing you may need to make another half or whole batch of icing.
Then let the icing harden for a 1-2 hours at room temp.
Once the icing sets the cookies will be stackable for storing or gifting.
Storing
Keep your Iced Oatmeal Cookies in a covered container at room temp for up to 5 days, although they probably won't last that long!
You can keep them longer, up to 10 days, in the fridge.