Wash your broccoli thoroughly under cool running water. Cut the head into bite-sized florets, making sure they're small enough to eat comfortably but large enough to maintain that satisfying crunch. Pat them dry with a clean kitchen towel.

Finely chop your red onion into small pieces. If you're sensitive to raw onion, this is the time to soak those pieces in cold water for a few minutes to mellow the sharpness.

In a large mixing bowl, add your broccoli florets, shredded mozzarella cheese, and chopped red onion. Give everything a gentle toss to distribute the ingredients evenly.

In a separate small bowl, whisk together the mayonnaise, white sugar, and white wine vinegar. Keep whisking until the mixture is completely smooth and the sugar has fully dissolved. This should take about a minute of steady whisking.

Pour your creamy dressing over the broccoli mixture. Using a large spoon or spatula, gently toss everything together until every piece of broccoli is beautifully coated. The salad should look glossy and inviting.

Cover the bowl with plastic wrap and refrigerate for at least thirty minutes before serving. This resting time allows the flavors to meld together and the broccoli to soften just slightly while maintaining its crunch.