Creamy Caramelized Cauliflower Pasta

Name: Creamy Caramelized Cauliflower Pasta
Ingredients: 8 ounces whole-wheat rotini (about 2¾ cups ); 3 tablespoons unsalted butter , divided; 1 small head cauliflower ( 1 pound ), cut into 1-inch florets ( 4 cups ); ¾ teaspoon salt; ¼ cup thinly sliced garlic (from 8 large garlic cloves ); 2 tablespoons water; 2 teaspoons fresh thyme leaves, plus more for garnish; ¾ teaspoon ground pepper , plus more for garnish; 2 tablespoons sherry vinegar; ½ cup sour cream; ¼ cup heavy cream; ½ cup grated Parmesan cheese , divided