1. Preheat the oven to 350 degrees F. Beat together the vegan butter and sugars, then add the peanut butter and the pure vanilla extract.
2. In a separate bowl, whisk together the gluten-free baking flour, baking soda and powder, and salt. Add the flour mixture to the bowl and beat on low until crumbs form, then add one tablespoon of plant milk and the cookie dough will come together nicely. Turn the beater off and then stir in the chocolate chips. Press the cookie dough evenly into an 8×8 parchment-lined baking pan and bake for 20 minutes. Remove from the oven and let the cookie bars cool completely before frosting.

To Make the Frosting

1. In a stand mixer (alternatively you can do this with a hand blender or mixer), cream the butter, vanilla, and cinnamon on medium speed until creamy, then slowly add the powdered sugar and keep blending until it thickens and looks like frosting. You'll then add plant milk 1 teaspoon at a time until you achieve the desired thickness.