Combine the almond flour, baking soda, baking powder, xanthan gum and salt in a bowl and set aside.Melt the butter in a microwave safe bowl.Add vanilla extract, liquid stevia, erythritol and an egg to the melted butter and combine.Add the dry ingredients to the wet mixture in two batches and mix thoroughly ensuring there are no clumps of flour.Cut up the bakers chocolate into as big or as little chunks as you want and add it to the batter.