Pat chicken breasts dry with paper towels and season both sides generously with salt, pepper, and Italian seasoning. Heat olive oil in a large skillet over medium-high heat for exactly 2 minutes until shimmering but not smoking—this achieves proper browning without burning.

Working quickly, place seasoned chicken in the hot skillet and cook undisturbed for 6–7 minutes until the bottom reaches deep golden-brown color. Flip and cook the other side for 5–6 minutes until internal temperature reaches 165°F. Transfer to a clean plate and tent loosely with foil.

In the same skillet, melt 1 tablespoon butter over medium-high heat and add sliced mushrooms in a single layer. Allow mushrooms to sit undisturbed for 3 minutes to develop caramelization, then stir and cook another 4 minutes until golden. This step releases the umami that defines your creamy mushroom chicken elegant presentation.

Add remaining 1 tablespoon butter and minced garlic to the mushroom pan; cook for exactly 60 seconds until fragrant. Pour in white wine and use a wooden spoon to scrape up all browned bits from the pan bottom—this deglazing step adds complexity that separates restaurant-quality cooking from ordinary.

Reduce heat to medium and stir in chicken broth, then slowly pour in heavy cream while whisking constantly to prevent lumps. Add Dijon mustard and Parmesan cheese, whisking until the sauce reaches silky smoothness. Simmer for 2 minutes until sauce coats the back of a spoon.

Return chicken to the skillet, nestling it into the sauce, and simmer for 3–4 minutes to reheat and allow flavors to meld. Finish with fresh lemon juice and scattered parsley. The finished dish should glisten with creamy elegance, ready for plating.