Cream together 1/4 cup brown sugar, 2 Tablespoons unsalted butter, and 1/8 teaspoon kosher salt in a medium bowl using a hand mixer or wooden spoon. Add 1/4 teaspoon vanilla extract and stir until incorporated. Add the oat flour and stir until mixed. Mix in 2 Tablespoons chocolate chips. Eat as is, or use as a topping for ice cream.