01 - Melt butter in a large pot or Dutch oven over medium heat. Add the onion and carrots, sautéing for 5 minutes until softened and translucent.
02 - Stir in the minced garlic and cook for 1 minute until fragrant, being careful not to let it brown.
03 - Sprinkle flour over the vegetables and stir well to combine. Cook for 1 minute to remove the raw flour taste and form a light roux.
04 - Slowly pour in the chicken broth while stirring constantly to prevent lumps from forming. Bring the mixture to a gentle simmer.
05 - Add the diced chicken, dried thyme, salt, pepper, and nutmeg if using. Simmer for 8 to 10 minutes until the chicken is cooked through and tender.
06 - Stir in the orzo pasta and cook for 7 to 8 minutes, stirring occasionally to prevent sticking, until the orzo is tender.
07 - Reduce the heat to low. Pour in the heavy cream and add the grated Parmesan cheese. Stir until the cheese is fully melted and the soup reaches a creamy, velvety consistency.
08 - Gently fold in the chopped spinach and cook for 2 to 3 minutes until just wilted. Taste and adjust seasoning with additional salt and pepper as needed.
09 - Ladle the hot soup into bowls and garnish with freshly chopped parsley if desired. Serve immediately alongside crusty Italian bread.