Add the frozen blueberries to the blender along with a splash of water or sparkling water to help blending.
Squeeze in the fresh lemon juice and add the mint leaves to the blender.
If you prefer a sweeter slushie, drizzle in honey or agave syrup.
Secure the lid on the blender and blend on high until the mixture is thoroughly smooth and icy, about 30 seconds.
Stop the blender and check the texture; if it's too thick, add a little more water or sparkling water and blend briefly to loosen it up.
Pour the vibrant purple slushie into glasses, using a spoon to help fill if needed.
Garnish with extra mint leaves or a few fresh blueberries for a beautiful presentation.
Serve immediately with a straw or spoon for a refreshing, icy treat.