Pat the chicken breasts completely dry with paper towels. This is crucial for achieving a good sear. Season both sides generously with salt and freshly ground black pepper.

Heat the olive oil in a large skillet over medium-high heat until shimmering. Carefully place the seasoned chicken breasts in the hot skillet, ensuring not to overcrowd the pan (cook in batches if necessary). Sear for about 5-7 minutes per side, or until golden brown and cooked through. The internal temperature should reach 74°C (165°F). Remove the chicken from the skillet and set aside on a plate.

Reduce the heat to medium. Add the butter to the same skillet. Once melted, add the minced garlic and cook for about 1 minute until fragrant, being careful not to burn it.

Stir in the chopped sun-dried tomatoes and optional red pepper flakes. Cook for another minute, allowing the tomatoes to soften slightly and release their flavor into the butter.

Pour in the chicken broth and heavy cream. Bring the mixture to a gentle simmer, scraping up any browned bits from the bottom of the skillet. Let it simmer for about 3-5 minutes, or until the sauce has slightly thickened.

Reduce the heat to low. Gradually whisk in the grated Parmesan cheese until it's fully melted and the sauce is smooth and creamy. Taste and adjust seasoning with salt and pepper if needed.

If using spinach, add it to the sauce now and stir until it just begins to wilt. This adds a lovely pop of color and freshness.

Return the seared chicken breasts (and any accumulated juices) to the skillet, nestling them into the creamy sauce. Spoon some of the sauce over the chicken. Let it simmer gently for 1-2 minutes to heat the chicken through and allow the flavors to meld.

Serve the Marry Me Chicken immediately, spooning extra sauce over each piece. It pairs wonderfully with pasta, crusty bread, or a side of steamed vegetables.