Preheat oven to 300*. Line sheet pan with parchment.
Whisk egg whites with ballon whisk attachment in Kitchen Aid on high until very frothy.
Stop mixing. Add salt, vanilla, cream of tartar, and xanthin gum.
Whisk on high speed until soft peaks form.
Lower speed and add Swerve 1 tablespoon at a time pausing after each addition.
Return to high speed and whisk until stiff peaks form.
Divide into 3 equal bowls and ad a drop or 2 of food coloring, if desired.
Mix each color till fully combined.
Spoon colored meringues onto parchment and smooth into a loaf shape.
Bake for 60 to 70 minutes. If top browns to much, place a seat panon the rack above to protect it.
Let cool.