Season the chicken: Pat the chicken dry with paper towels. Season with the salt, pepper, garlic powder, onion powder, and Italian seasoning, tossing until evenly coated.
1½-2 lbs. boneless skinless chicken cutlets, 1 tsp. kosher salt, 1/2 tsp. freshly cracked black pepper, 1 tsp. garlic powder, 1/2 tsp. Italian seasoning, 1/2 tsp. onion powder
Cook the chicken: Heat the avocado oil in a large, deep skillet over medium-high heat. Once hot, add the chicken in a single layer. Cook for about 5 minutes Start Timer, flip, and cook for another 5-7 minutes Start Timer. Remove to a plate.
1-2 Tbsp. avocado oil
Melt the butter: Reduce the heat to medium and add 3 tablespoons of the butter to the same skillet.
5 Tbsp. unsalted butter
Add the aromatics: Add the shallot to the butter and cook for 2-3 minutes Start Timer until softened. Stir in the garlic and cook for about 30 seconds, just until fragrant.
1 small shallot, 5 cloves garlic
Add the liquid: Pour in the chicken broth and heavy cream, scraping up any browned bits from the bottom of the skillet. Whisk in the Dijon mustard, 1/2 teaspoon salt, and a few cracks of black pepper. Bring to a gentle simmer.
2½-3 cups low-sodium chicken broth, 1/2 cup heavy cream, 1 tsp. Dijon mustard, 1/2 tsp. kosher salt, freshly cracked black pepper
Cook the noodles: Add the egg noodles and stir to coat. Cook uncovered for 7-9 minutes Start Timer, stirring frequently, until the noodles are tender. Keep the mixture at a gentle simmer rather than a rapid boil. If the noodles absorb the liquid before they're fully cooked, add additional chicken broth a few tablespoons at a time.
8 oz. wide egg noodles
Make it buttery & cheesy: Reduce the heat to low. Add the remaining 2 tablespoons of butter and Parmesan. Toss until the butter and Parmesan melt into the sauce and the noodles are glossy and creamy.
1/2-3/4 cup freshly grated Parmesan cheese
Add chicken: Return the chicken and any accumulated juices to the skillet. Toss to combine and gently warm the chicken through.
Finish: Remove the skillet from the heat. Add fresh parsley. Taste and adjust with additional salt and freshly cracked black pepper as needed. The sauce will continue to thicken as it sits, so serve right away with plenty of freshly grated Parmesan on top.
2 Tbsp. finely chopped fresh parsley