Place the blueberries in a heavy bottomed sauce pan with the xylitol, lemon juice, lemon zest and nutmeg if using. Bring to a boil then reduce heat to low and continue to cook while stirring occasionally for 15-20 minutes or until it has thickened slightly.
Sprinkle the xanthan gum over the surface and then blend in with a spoon, continue to cook for 1 minute then remove from heat and cool to room temperature. Adjust sweetness by slowly adding stevia to your taste. Once cool place in a glass jar or plastic container with a tightly fitting lid and keep refrigerated for up to 2 weeks. This may also be properly canned if desired. Makes 1 ΒΌ cups. Each serving is 2 Tbsp.