Pour the chilled rosé wine into the blender, followed by the ice cubes, sweetener, and lemon juice.
Secure the lid and blend on high speed until the mixture is smooth, icy, and slightly slushy—about 30 to 45 seconds. You should see a vibrant pink color with tiny ice shards.
Pause briefly to check the texture—if it's too runny, add a few more ice cubes and blend again until thickened.
Taste the slushie and adjust with more sweetener or lemon juice if desired, blending briefly to incorporate.
Once the mixture is a frosty, uniform pink with a thick, slushy texture, stop the blender.
Pour the cold, icy rosé slushie into chilled glasses to keep it frozen longer.
Serve immediately with a straw or small spoon, enjoying the refreshing, icy texture on a hot day.