To begin, line a 9x9 pan with parchment paper sticking out both sides, for easy removal.
To a large mixing bowl, add your butter, cashew butter and sugar and beat them together with a mixer till creamy. Add your coconut milk and vanilla and beat again till the mixture is smooth. Add your oat flour and salt, and mix again, till you have a thick cookie dough-like mixture. Add your chocolate chips and gently fold in.
Pour your cookie dough mixture into your pan and carefully spread it out, into one thin and even layer across the bottom of the pan. Put your pan in the freezer for 30 minutes.
Add your chocolate chips and cashew butter to a microwaveable bowl or pyrex. Microwave for 30 seconds, and stir your chocolate and cashew butter together. Microwave for another 30 seconds, stir again till smooth (if necessary microwave for another 15-20 seconds).
Take the cookie dough bars out of the freezer, and pour the chocolate topping on top. Spread across the top till you have a thin and even layer of chocolate.
Put the bars in the freezer again for at least one hour. Remove, cut into 16 bars, and devour!
Store these bars in an airtight container in either the fridge or freezer. They will last about a week in the fridge and a couple months in the freezer.