Preheat oven to 350° Fahrenheit and grease a baking sheet.
In a mixing bowl, cream together the butter and erythritol or cane sugar.
Add egg and mix well.
Add almond flour, vanilla, and salt; mix well.
Roll out dough on a surface dusted with additional almond flour.
Cut cookies and desired and transfer to baking sheet.
Bake for 15 minutes and cool.
In a food processor, combine the almond flour, coconut oil, cane sugar or erythritol, and vanilla.
Process until buttery.
Chill until thickened to the consistency of frosting.