In a small bowl, combine the salt, pepper, and flour. Dredge the chicken cutlets in the flour mixture (save any extra flour mixture). In a nonstick skillet, melt the 2 tablespoons of butter over and pan fry the chicken cutlets over medium high heat until browned on each side, about 2 minutes per side. The chicken doesn't have to be cooked all the way, just browned.
To the slow cooker, add the browned chicken, sprinkle over the remaining flour mixture. Then add the remaining butter, lemon juice, chicken stock, Dijon mustard, minced garlic, and capers. Cover and cook on high for 3.5 - 4 hours or until the chicken is tender.
Serve with desired sides and garnish with lemon and parsley if desired.