Place the blueberries, basil leaves, ice cubes, honey, and water into the blender.
Secure the lid and blend on high speed until the mixture is smooth and frosty, about 30-40 seconds. The berries should be fully broken down and the basil evenly incorporated.
Stop the blender and check the texture; if it’s too thick, add a splash more water and blend briefly to loosen.
Pour the slushie into two chilled glasses, allowing the icy purple nectar to flow smoothly.
Garnish each glass with a fresh basil leaf or a few blueberries for a vibrant presentation.
Serve immediately with a straw and enjoy the cool, herbaceous burst of flavors.