In a large skillet, heat the butter/olive oil. Season the chicken breasts with salt and pepper and cook them for 1-2 minutes on each side, until nicely browned but not cooked all the way through.
Remove the chicken to the slow cooker. In a large bowl, combine all the other ingredients. Whisk well. Pour the sauce over the chicken.
Cover the crockpot and cook on low for 6 hours. Serve with rice or noodles.
