Preheat the oven to 350 degrees.
In a large bowl combine the oat flour and cocoa powder.
Blend the chickpeas and almond milk until totally smooth, and add to the dry ingredients.
Add the date paste and stir until everything is combined.
Fold in the chocolate chips, and pour the batter into a nonstick or sprayed square pan.
Bake for 40 minutes.
Let the brownies cool in the pan for at least 1 hour.
To make the frosting, combine all the ingredients except chocolate chips in the food processor and blend until totally smooth, thick and creamy.
Spoon cookie dough into a bowl and mix in the vegan chocolate chips - make sure the mixture isn't hot from blending so the chocolate chips don't melt.
Spread the cookie dough frosting over the cooled brownies.
Store leftovers in the refrigerator.