Chicken Tortellini Alfredo

Name: Chicken Tortellini Alfredo
Ingredients: 3/4 teaspoon kosher salt , plus more for cooking water; 2 (9-ounce) packages refrigerated three-cheese tortellini (such as Buitoni); 2 large egg yolks; 1/4 cup unsalted butter; 2 medium garlic cloves , finely chopped (about 2 teaspoons); 1 1/2 cups heavy whipping cream; 4 1/2 ounces Parmigiano-Reggiano cheese , finely grated (about 1 cup); 3 cups cubed or torn cooked chicken breast (about 14 ounces); 2 teaspoons coarsely chopped fresh flat-leaf parsley; 1 teaspoon fresh thyme leaves; 1 teaspoon grated lemon zest (from 1 lemon); Black pepper