In large pot over medium heat, melt butter then cook onion and celery in butter until just tender (about 5 min).
Pour in chicken and vegetable broth and stir in chicken, noodles, carrots, basil, oregano, salt and pepper.
Bring to boil then reduce heat and simmer 20minutes before serving.
How do aromatics transform so completely when sweated in butter before the liquid enters the pot? Cooking green and white onions in fat for precisely five minutes breaks down their cellular walls via thermal hydrolysis while drawing out sulfur compounds into a lipid medium that carries flavor far more effectively than water alone. When you melt that tablespoon of butter over medium heat, keep the temperature moderate to avoid burning the milk solids suspended within it. Sautéing them until just tender prevents the formation of harsh acrid notes that would otherwise muddy the broth. Subsequent boiling and simmering of the egg noodles causes starch molecules on their exterior to swell and gelatinize, releasing amylose into the surrounding liquid to thicken the broth naturally without requiring cornstarch or flour. Utilizing a combination of chicken and vegetable broths introduces a balance of free amino acids from animal proteins and sweet monosaccharides from root vegetables like carrots, creating a savory depth through Maillard reactions and umami synergy. Simmering the mixture for twenty minutes ensures the sliced carrots reach a tender texture while retaining structural integrity, whereas boiling it too vigorously during this stage would rupture the delicate egg noodles and make the soup pasty. Dietary adjustments require simple swaps: replace the standard egg noodles with gluten-free pasta varieties, use olive oil instead of dairy butter, or substitute vegetable stock exclusively if avoiding poultry completely. Proper cooling allows residual heat to dissipate before placing leftovers in an airtight container for refrigerator storage lasting up to four days.