Measure out the whiskey, simple syrup, ice cubes, and cold water, placing everything nearby for easy access.
Add the ice cubes to the blender first, creating a base that starts to crush as the blades turn.
Pour the whiskey and simple syrup over the ice in the blender, giving the mixture a sweet, spirited aroma.
Pour in the cold water, which helps achieve a smooth, slushy consistency once blended.
Secure the lid on the blender and blend on high for 30-45 seconds, until the mixture is icy, thick, and smooth with a glossy surface.
Once blending is complete, check the texture—it should be uniformly frozen and scoopable, like a soft snow cone.
Pour the whiskey slushie into chilled glasses, allowing the icy blend to mound attractively in each serving.
Optionally, garnish with a twist of lemon peel or a cherry for a colorful finishing touch.
