Line a baking sheet with parchment.
In a large saucepan over medium heat, combine the coconut oil, sugar, milk, and cocoa powder. Stir gently until everything is dissolved and the coconut oil is melted.
Stop stirring and allow to boil for 90 seconds undisturbed.
Remove from heat and stir in vanilla extract, salt, and cinnamon.
Once smooth, add the oats and stir to coat evenly. Mixture will be very stiff.
Work quickly, scooping 1 tbsp/15ml size amounts on to the parchment lined tray.
Form each cookie by rolling the dollop into a ball and pressing flat with your fingers or the bottom of a glass. Wetting your fingers or the glass can prevent the dough from sticking to it.
Once all the cookies are formed place the tray in the fridge to let the cookies set for at least 30 minutes.
Store cookies in the fridge for up to 1 week or in the freezer for 1 month.