Warm the butter and olive oil in a large pot over medium heat. Add the onion, celery, and carrots and cook, stirring, until just beginning to soften, about 5 minutes.

Stir in the garlic, thyme, salt, and pepper and cook until fragrant, about 30 seconds.

Pour in the chicken broth and add the bay leaf. Bring to a boil, then reduce to a gentle simmer and cook until the vegetables are tender, 10 to 12 minutes.

Stir in the egg noodles and simmer until al dente, 6 to 8 minutes (check package timing).

Add the shredded chicken and cook until heated through, 2 to 3 minutes. Remove the bay leaf, stir in the parsley and lemon juice, and adjust salt and pepper to taste. Ladle into bowls and serve hot.