Pour the chilled cola soda into a shallow dish or baking tray, spreading it out evenly.
Place the dish in the freezer and let it freeze for at least 4 hours, until the soda is solid or just beginning to form a slush.
Remove the frozen cola from the freezer and break it into smaller chunks with a fork, exposing more surface area for blending.
Transfer the frozen chunks into a blender and pulse until the mixture begins to break apart.
Blend on high speed until the mixture becomes smooth and velvety, with a slushy, semi-frozen texture.
Pour the Coke slushie into glasses, and serve immediately for the best icy texture.
