Prep the chicken: Pat chicken dry.
Season both sides with salt, pepper, and Italian seasoning.
Optional sear: Heat olive oil in a skillet over medium-high. Sear chicken 2–3 minutes per side until lightly golden. This step adds flavor but is not required.
Layer the slow cooker: Add chicken to the crockpot.
Sprinkle in the minced garlic. Pour in the chicken broth.
Add the creamy base: Dot the cream cheese cubes over the chicken. Sprinkle in red pepper flakes if using.
Cook low and slow: Cover and cook on Low for 3.5–4.5 hours or on High for 2–3 hours, until chicken is tender and reaches 165°F.
Finish the sauce: Transfer chicken to a plate.
Whisk the liquids in the crockpot until smooth, then stir in heavy cream, Parmesan, butter, and lemon juice. Whisk until the sauce is creamy and slightly thickened. Adjust salt and pepper.
Shred or slice: Shred chicken with two forks or slice it.
Return it to the sauce and stir to coat.
Serve: Spoon over pasta, rice, or mashed potatoes. Top with extra Parmesan and chopped parsley.
Optional add-ins: Stir in a handful of baby spinach during the last 10 minutes, or fold in sautéed mushrooms for extra savoriness.