Season the chicken breasts evenly with salt and black pepper on both sides.
Heat olive oil in a large skillet over medium-high heat. Sear the breasts for 5 to 7 minutes per side until golden brown and cooked through. Remove and set aside.
In the same skillet, melt the butter over medium heat. Add minced garlic and cook for 1 minute until fragrant.
Stir in the chopped sun-dried tomatoes, heavy cream, and Parmesan cheese. Simmer for 2 to 3 minutes until the sauce thickens slightly.
Add the baby spinach to the sauce and stir until wilted.
Return the seared chicken to the skillet, spooning the creamy sauce over the top. Serve immediately.