Prep the chicken: Pat the chicken dry and season both sides with salt and pepper. If you have time, sear in a hot skillet with olive oil for 2 to 3 minutes per side.
This step is optional but adds great flavor.
Layer the crockpot: Place chicken in the slow cooker. Sprinkle on garlic, Italian seasoning, and red pepper flakes.
Add liquids and cheese: Pour in the chicken broth and heavy cream. Add the cream cheese cubes and half of the parmesan.
Add sun-dried tomatoes: Scatter them over the top.
They’ll infuse the sauce with a deep, tangy flavor.
Cook low and slow: Cover and cook on Low for 3.5 to 4.5 hours (for breasts) or 4 to 5.5 hours (for thighs). Chicken should reach 165°F and be tender.
Shred or slice: Remove chicken and shred with two forks or slice into thick pieces. Return it to the crockpot.
Finish the sauce: Stir in spinach, remaining parmesan, and basil.
Cover and cook on Low for another 5 to 10 minutes until spinach wilts and sauce is silky.
Adjust and brighten: Taste and add salt, pepper, and a touch of lemon zest or juice if desired. Sauce should be rich and balanced.
Serve: Spoon chicken and sauce over zoodles, cauliflower mash, sautéed greens, or roasted veggies. Garnish with extra parmesan and basil.