Pre-heat oven to 350*F.
In a large bowl, beat together your butter and sweetener until light and fluffy. Add your egg and extracts and beat once more until combined.
Add the green food colouring a tiny amount at a time and beat it into the batter until you like the colour.
In another bowl, whisk together all of your dry ingredients including; almond flour, coconut flour, arrowroot starch, xanthan gum and salt.
Pour the dry ingredients into the wet and stir well until the dough becomes thick and everything is incorporated together.
Grease a cookie sheet then begin rolling balls of dough and placing them on the baking sheet, spaced evenly apart.
Flatten each cookie slightly (see photo) then bake for 9-11min. The cookies will be soft when they first come out but the bottoms should be lightly browned. They will continue to firm up as they cool. Once the cookies have fully cooled, you can transfer them to another tray or plate and make the frosting.
For the frosting, just mix the first 3 frosting ingredients in a small bowl until thick (it should be thick enough to pipe so make sure not to add too much water) then add the red gel food colouring as well.
Place the frosting in a small ziplock bag and cut off a very small corner (or put it in a piping bag with a fine tip) and pipe small hearts on the cookies. You can fill them in or just pipe the outside of the hearts.
Let the frosting harden on the cookies before serving. Enjoy your Keto Grinch Christmas Cookies!