Prep the chicken: Pat chicken dry and season both sides with salt, pepper, and Italian seasoning. Pounding to an even 1/2–3/4 inch helps it cook fast and stay juicy.
Sear until golden: Heat 1 tablespoon olive oil in a large skillet over medium-high heat.
Add chicken and cook 4–6 minutes per side, until nicely browned and cooked through. Transfer to a plate and tent with foil.
Sauté aromatics: Lower heat to medium. Add remaining 1 tablespoon olive oil.
Stir in garlic for 30 seconds, then add sun-dried tomatoes. Cook 1 minute until fragrant.
Deglaze: Pour in chicken broth, scraping up browned bits. Simmer 2–3 minutes to reduce slightly.
Build the sauce: Stir in heavy cream and Parmesan.
Keep heat at medium-low and whisk until smooth and slightly thickened. If you want it thicker, whisk 1 teaspoon cornstarch with 1 tablespoon cool water and stir in. Simmer 1 minute.
Add yogurt off heat: Remove skillet from heat.
Whisk in Greek yogurt until the sauce turns creamy and glossy. Return to low heat only if needed to warm gently—do not boil.
Finish with greens: Fold in spinach and let it wilt, 1–2 minutes. Add lemon juice if using.
Taste and adjust salt and pepper.
Return chicken to pan: Nestle chicken into the sauce and spoon sauce over the top. Warm for 1–2 minutes to meld flavors.
Serve: Garnish with fresh basil. Pair with pasta, rice, or a veggie mash to catch the extra sauce.