Pour the granulated sugar into a saucepan and cook over medium heat, swirling gently to evenly melt the sugar until it becomes a golden amber caramel aroma fills your kitchen.
Once the sugar is fully melted and golden, carefully pour in the heavy cream—listen for a gentle bubbling—and whisk briskly to smooth out the mixture. Add a pinch of sea salt if desired, then remove from heat and let the caramel cool slightly.
Transfer the slightly cooled caramel into a sturdy blender, then add the ice cubes, milk, and vanilla ice cream. Secure the lid tightly and start blending on low speed, gradually increasing until the mixture is thick, frosty, and uniformly blended—about 30-60 seconds.
Stop the blender, and check the texture—there should be a smooth, slushy consistency with tiny ice shards. If needed, add a few more ice cubes and give it a quick blend again until it reaches your desired thickness.
Pour the caramel slushie into chilled glasses, and optionally drizzle with extra caramel or sprinkle a pinch of sea salt on top for presentation and flavor contrast.
Savor this frozen treat immediately with a straw or spoon, enjoying the rich caramel flavor combined with icy coolness to refresh and delight your senses.
