Heat 1 TBS butter in a large skillet over medium high heat until it sizzles.
Sprinkle 1/2 of the salt, pepper, and Italian seasoning over top of chicken breasts. Place seasoning side of chicken upside down into the pan with sizzling butter. Then season the top of chicken with the other 1/2 of the salt, pepper, and Italian seasoning.
Cook chicken for 3 minutes until browned. Flip over chicken and cook an additional 3 minutes. Spray crockpot with a non-stick cooking spray. Place browned chicken into crockpot. Place one pat of butter onto each chicken breast.
In same large skillet over medium high heat, add 1 TBS of butter to deglaze the pan. Stir, scraping the bits off of the bottom of pan (this is flavor, so don't wipe out the pan). Stir in the chicken broth, bouillion, garlic and lemon zest and juice. Cook for 1 minute. Turn off heat. Pour sauce over chicken in the crockpot.
Place lid on and cook for 3-4 hours on low or 2-3 hours on high. It will depend on how thick the chicken breasts are.
Once chicken is cooked through thicken the sauce. Remove the chicken or just stack the chicken on top of each other in the crockpot. Whisk together corn starch and heavy cream. Pour into crockpot. Add parmesan cheese, 1/4 tsp black pepper and lemon slices. Stir altogether. Place chicken back into sauce. Cover Crockpot and cook on high 1 hour.
Serve over rice, mashed potatoes or pasta.
