Add the frozen blueberries to your blender, ensuring they are evenly spread out for smooth blending.
Drizzle in the honey, measuring carefully to balance sweetness, and squeeze in the lemon juice for brightness.
Pour in the cold water to help the mixture blend smoothly and achieve a slushy texture.
Secure the lid on the blender and blend on high until the mixture is thick, icy, and uniformly smooth, about 30-40 seconds. You should hear a consistent whir and see the mixture turn a vibrant purple-blue color.
Stop the blender and check the consistency; if it's too thick, add a splash of cold water and blend again briefly.
Pour the slushie into glasses, and garnish with a small basil sprig or a few blueberries if desired for a pretty presentation.
Serve immediately while icy and chilled, enjoying the bright, refreshing flavors with a hint of herbal aroma.
