In a large stock pot, melt butter over medium-high heat. Add diced celery and carrots, sautéing for 3 minutes. Stir in minced garlic and cook for an additional 30 seconds.

Pour in the chicken broth and season with rosemary, sage, crushed red pepper, salt, and black pepper. Bring to a boil, then taste and adjust seasoning as needed.

Add the dry egg noodles to the boiling broth and cook until al dente, usually about 7-8 minutes, depending on the noodle type.

Once noodles are cooked, remove the pot from heat to prevent overcooking. The noodles will continue to soften in the hot broth.

Stir in the shredded cooked chicken and let it warm through in the hot soup. Do a final taste test and adjust any seasonings if necessary.

Serve hot, and store any leftovers in an airtight container in the refrigerator for up to 4-5 days.