Pat the chicken breasts dry and season generously with salt and pepper. Heat olive oil in a large skillet over medium heat until shimmering.
Place the chicken in the hot skillet and sear for 5-6 minutes on each side until golden brown and cooked through. If the breasts are thick, finish in a 180°C oven for about 10 minutes. Remove from skillet and set aside to rest.
Add the chopped garlic to the same skillet and sauté for about 30 seconds until fragrant, stirring constantly to prevent burning.
Add the soaked sun-dried tomatoes to the skillet and cook for 2 minutes, stirring to release their smoky aroma.
Pour in the heavy cream and chicken broth, scraping up any browned bits from the bottom of the pan. Bring to a gentle simmer and cook for 3-4 minutes until the sauce begins to thicken and coats the back of a spoon.
Add the chopped spinach to the skillet and stir until wilted, about 1-2 minutes. Squeeze in the juice of half a lemon and stir to brighten the sauce.
Return the cooked chicken to the skillet, spooning sauce over the top. Cook for another 2 minutes until heated through and flavors meld.
Remove from heat and let rest for 3 minutes. Serve the chicken topped with the creamy sauce, garnished with extra lemon zest or herbs if desired.