Line an 8 x 8-inch baking dish with parchment paper and set aside.
In a large mixing bowl, whisk together the oat flour, coconut flour, vanilla protein powder, 1 tablespoon cinnamon, and 2 tablespoons sugar until evenly combined.
In a microwave-safe bowl, combine the almond butter and brown rice syrup and heat in 15–20 second intervals, stirring, until melted and smooth. Stir in the vanilla extract.
Pour the melted almond-brown rice syrup mixture into the dry ingredients and stir until the mixture becomes crumbly.
Add the 2 tablespoons milk one tablespoon at a time, mixing after each addition, until a thick, firm batter forms.
Transfer the batter to the prepared pan and press firmly and evenly to compact.
Mix the topping cinnamon and sugar together, rub or sprinkle it evenly over the pressed bars, then refrigerate for at least 30 minutes to set before cutting into 12 bars.
