Creamy Cajun Chicken Pasta Soup

Name: Creamy Cajun Chicken Pasta Soup
Prep time: 15 min
Cook time: 30 min
Total time: 45 min
Cuisine: American, Cajun And Creole
Ingredients: 2 tablespoons butter; 1 small white onion (chopped); 4 cloves garlic (minced); 2 tablespoons cajun seasoning (divided); 5 cups chicken stock (or 4 cups chicken stock + 1 cup water); 1 14.5-ounce can diced tomatoes (undrained); 1 cup heavy cream (at or close to room temperature); 1 cup ditalini (or other small pasta, dry); 1 pound chicken breasts or tenders (see Notes); 1 tablespoon neutral oil; 1 cup freshly grated parmesan (at room temperature, see Notes); salt and pepper (to taste); green onions (sliced, to garnish)