Place the cherries, sugar syrup, and lemon juice into the blender.
Blend on high speed until the mixture is smooth, and the cherries are fully broken down. You should see a vibrant red liquid with a slightly frothy top.
If the mixture is too thick, add a splash of water or lemon juice to loosen it up and blend again for a few seconds.
Check the consistency—if it’s icy and slushy, it’s ready. If not, briefly pulse a few more times until desired texture is achieved.
Pour the cherry slushie into glasses, allowing the vibrant red color to fill the glass completely.
Serve immediately with a straw or garnish with a fresh cherry or a lemon wedge for a fun touch.