In a large stockpot, melt the butter over medium-high heat.
Add diced celery and carrots and sauté for about 3 minutes until slightly softened.
Add minced garlic and cook for 30 seconds until fragrant.
Pour in the chicken stock and season with rosemary, thyme, crushed red pepper, salt, and black pepper. Stir well and taste the broth.
Add chicken bouillon paste or granules if needed to deepen the flavor.
Bring the soup to a gentle boil.
Add noodles and cook until just al dente.
Remove from heat promptly to prevent overcooking the noodles.
Stir in the cooked chicken. Taste again and adjust seasoning as needed.
Serve hot.