Place the butter and oil in a skillet. Heat over medium heat until butter is melted.

Season ribs with salt and pepper and place in the skillet.

Brown ribs on all sides. Remove from skillet and place in the slow cooker and sprinkle with the ranch dressing mix.

In a bowl, combine the ketchup, mustard, Worcestershire sauce, vinegar, lemon juice, and brown sugar. Once blended pour over the ribs in the slow cooker.

Cover and cook on high for 4 hours.

Carefully remove cooked ribs from the crock pot. They will be very tender.

In a small bowl, mix together the cornstarch and water until well blended. Add cornstarch mixture to the sauce remaining in the slow cooker. Stir in to thicken sauce. Serve ribs with sauce. Can be served over cooked rice.