Pour the chilled champagne into the blender, ensuring it’s at a steady, bubbly flow.
Add the simple syrup to the champagne, balancing sweetness and giving it a smooth, sweet flavor.
Squeeze in the lemon juice for a subtle citrus brightness that complements the bubbles.
Pour in water to help the mixture blend smoothly and to achieve the right icy texture.
Drop in the ice cubes to give the slushie its signature frozen, icy consistency.
Blend on high speed until the mixture is smooth, frosty, and has a syrupy, slushy texture with tiny ice crystals.
Taste the slushie and adjust sweetness or acidity if needed, then give one last quick blend.
Pour the chilled champagne slushie into tall glasses, adding a few extra ice cubes if desired to keep it icy.
Garnish with a twist of lemon or a fresh berry for an elegant touch before serving.