2 1/2 to 3 lb. country style pork ribs, boneless
1 tbsp. oil
1 large onion, quartered & sliced 1/4- to 1/2-inch thick
.
Sauce:
1/3 cup low sodium soy sauce
1/2 cup tomato ketchup
1 tbsp. prepared mustard
3 tbsp. brown sugar
2 cloves garlic, minced
Dash black pepper
2 tbsp. apple cider vinegar
1 teaspoon celery seed

Trim excess fat from ribs. In a large skillet, brown ribs in oil; transfer to the slow cooker. Place onion slices over the pork ribs. Combine all remaining ingredients; pour over ribs and onions.Cover and cook on low for 8 to 10 hours.
Serves 6.