Heat the oil in a large Dutch oven over medium-high heat until shimmering. Add the onion, carrots and celery and cook until softened, about 5-7 minutes. Add the garlic and cook, stirring, until fragrant, about 30 seconds.
Add the thyme, bay leaf, broth and chicken. Bring to a boil (this might take 5-10 minutes), then reduce the heat and gently simmer the soup, uncovered, until the vegetables are tender, about 15 minutes.
Stir in the noodles and cook until just barely al dente, about 5 minutes. Remove from heat and stir in parsley and lemon juice (if using). Season with salt and pepper, to taste.
Notes
Don't overcook the noodles or they will become mushy in your soup. Add them to the pot just before you're ready to serve.
What can I add to Chicken Noodle Soup for flavor? This recipe includes fresh herbs like thyme and parsley, as well as garlic and bay leaf for more seasoning. If you like an even stronger, richer tasting soup, feel free to add more of your favorite herbs like dill, basil, oregano, rosemary, or chives, or a spice blend like poultry seasoning.
Taste and season as you go. The total amount of salt necessary will vary depending on the saltiness of your broth, and on personal preference. Add extra salt for more flavor, and feel free to increase the other herbs and seasonings as well. Start with low sodium chicken broth if you're sensitive to sodium, since many store-bought options can be quite salty.
A fresh parsley garnish and the lemon juice at the end gives each bowl a pop of color and a bright touch. These are optional, though!
If you'd like to prepare a batch of the soup in advance, I recommend making the soup through Step 2 (do not add the noodles). Cool the broth and store in an airtight container in the fridge for up to 3 days, or in the freezer for up to 1 month. When ready to serve, bring the soup to a simmer, add the noodles, and follow the rest of the recipe.
Leftover soup will keep in the refrigerator for 3-4 days or in the freezer for up to 1 month; however, cooked noodles may be mushy when frozen and reheated.