Season your chicken breasts with Italian seasoning, salt, and pepper. Heat olive oil in a large skillet over medium heat.
Add the chicken and sear on both sides for 3-4 minutes until golden brown. Remove from the skillet and set aside; you’ll finish cooking them in the sauce later.
Using the same skillet, add your chopped onions and garlic. Cook for about 2-3 minutes, stirring until fragrant and slightly softened. Toss in the sun-dried tomatoes and stir briefly to release their flavors.
Next, add the fresh spinach to the pan. Stir it gently, letting it wilt down into the other ingredients. It might seem like a lot at first, but it quickly reduces in volume as it cooks.
Stir in the heavy cream, then sprinkle in the grated parmesan cheese. Allow the sauce to simmer, thickening slightly as it bubbles. Taste the sauce and adjust with more salt or pepper if required.
Nestle the seared chicken breasts back into the skillet, spooning the sauce over them.
Cover and cook for another 5-7 minutes, letting the chicken soak up the rich flavors and finish cooking through. By the time it’s ready, the sauce will be creamy, and the chicken tender!