Heat the olive oil in a skillet on the stove over medium-high heat. When the pan is hot, add the chicken thighs. Sprinkle with some salt and pepper. Brown the chicken on both sides, 2-4 minutes per side. Transfer chicken to the slow cooker.
Reduce the heat to medium and add the shallots to the pan. Sauté, stirring constantly, for 1 minute. Add the garlic and sauté for 30 seconds.
Pour the chicken broth into the pan and cook for 1 minute, gently scraping up any browned bits from the bottom of the pan. Turn off the heat.
Transfer the contents of the pan to the slow cooker.
Add the Italian seasoning, ¼ teaspoon salt, ¼ teaspoon pepper and sun-dried tomatoes to the slow cooker.
Cover and cook on high heat for 2-2.5 hours or low for 4-5 hours, until chicken is cooked to an internal temperature of 165° F.
In a small bowl, whisk together the cream and cornstarch. Stir it into the slow cooker, along with the spinach. Cook for 5-10 minutes, until the sauce thickens slightly.
Taste and season with additional salt and pepper, if needed. Serve with grated Parmesan cheese, if desired.
