Begin by heating the olive oil in a large skillet over medium-high heat. While the oil is warming, season both sides of the chicken breasts generously with salt and pepper.
Once the skillet is hot, carefully add the chicken breasts. Sear them for approximately 5-7 minutes on each side, or until they achieve a beautiful golden-brown crust and reach an internal temperature of 165°F (75°C). After cooking, remove the chicken from the skillet and set it aside on a plate to rest.
Into the same skillet (to retain all those lovely flavors), add the minced garlic. Sauté for about 1 minute, or until the garlic becomes fragrant and just begins to turn golden - be careful not to burn it!
Slowly pour in the heavy cream, stirring to incorporate. Bring the mixture to a gentle simmer, allowing it to start thickening slightly.
Next, add the chopped spinach, sun-dried tomatoes, Italian seasoning, and grated Parmesan cheese. Stir continuously until the cheese is fully melted and the sauce becomes rich and creamy.
Return the seared chicken breasts to the skillet, allowing them to bask in the creamy sauce. Spoon the sauce over each breast and let everything simmer together for an additional 2-3 minutes, ensuring that the chicken is heated through and well-coated with the sauce.
Taste the sauce and adjust the seasoning with a pinch more salt and freshly cracked black pepper, if necessary.
To serve, arrange the creamy chicken on plates, generously spooning sauce over the top. Garnish with fresh basil leaves for a pop of color and freshness.