Add the hibiscus syrup and fresh lemon juice.

Sprinkle the xanthan gum evenly over the liquid ingredients.

Add the ice cubes on top.

Blend on low speed for several seconds to begin breaking down the ice.

Increase to high speed and blend until the mixture becomes thick, smooth, and evenly colored.

Stop and scrape down the sides if needed to ensure an even texture.

Continue blending until no large ice pieces remain and the slush looks velvety.

Pour immediately into a chilled serving glass.

Garnish with a lemon slice or fresh mint and serve right away.