1tablespoonBob's Red Mill Egg Replacermixed with 2 tbsp water
For the buttercream frosting:
½cup (113g)unsalted butterroom temperature
1 ½cups (180g)powdered sugar
Preheat oven to 350°F. Line a square baking pan with parchment paper and set aside.
In a small bowl, whisk the flour, baking powder, and salt together. Set aside.
Using a hand mixer or a stand mixer fitted with the paddle attachment, cream the butter with both sugars until combined. Add the egg replacer and vanilla extract and continue to beat.
Add the dry ingredients and mix on low speed until combined. Pour into prepared pan and bake for 16-18 minutes, or until the edges are slightly browned. Allow to cool completely before removing from the pan.
To make the buttercream frosting:
Using a hand mixer or a stand mixer fitted with the paddle attachment, beat the butter until smooth. Add in the powdered sugar and continue to mix until combined.
Add milk, one tablespoon at a time, and beat to achieve the desired consistency. Add gel food coloring, if using, and mix well. Spread frosting on cooled cookie base before slicing into bars.
Be sure to follow the instructions on the package of Bob's Red Mill Egg Replacer. Once mixed with water, the egg replacer must sit for just a few minutes to thicken.
If you are not looking to replace eggs, you should be able to use 1 egg instead of the egg replacer.
If you accidentally thin your frosting out too much with the milk, add more powdered sugar in, one tablespoon at a time.