Cut the mozzarella into 1-inch cubes and place in a large bowl.
In a separate bowl, whisk together olive oil, red wine vinegar, Dijon mustard, honey, minced garlic, oregano, salt, and black pepper until well combined.
Pour the dressing over the mozzarella cubes and gently toss to coat. Cover the bowl with plastic wrap and refrigerate for at least 1 hour, or up to 4 hours, stirring occasionally.
Just before serving, stir in the torn basil leaves and drain any excess liquid from the mozzarella.
Notes
For best results, use high-quality mozzarella and serve chilled.