In a large saucepan, season the chicken broth with the garlic powder and pepper. Bring to a boil and add lemon juice and pasta. Cook over medium heat, stirring occasionally, until all liquid is absorbed, about 25 minutes.
Stir chicken into cooked pasta, along with the cream, parmesan cheese and lemon zest. Cook, stirring, over low heat for 5 minutes.
Remove from heat and let stand 5 minutes. Stir thoroughly before serving.