Add the crushed ice to your blender until it's about halfway full, creating a base for the slushie.
Pour the blue raspberry syrup over the ice, ensuring even coverage for vibrant color and flavor distribution.
Secure the lid on the blender and blend on high speed until the mixture is smooth, evenly icy, and has a slightly thickened, slushy texture—about 30 seconds.
Check the consistency; if it's too thick, add a splash of cold water or more syrup and blend briefly to loosen it up.
Pour the blended slushie into chilled glasses, allowing the icy mixture to mound slightly above the rim for a generous presentation.
Serve immediately with colorful straws or a sprig of mint for a fun, visual touch, and enjoy the refreshing, icy texture.