Smothered Country-Style Ribs

This is bar none the BEST slow cooker ribs I've ever tasted!  Last time I made them, I served them with Awesome and Easy Creamy Corn Casserole and baked beans.

The recipe comes from the cookbook Slow Cooker Comfort Food by Judith Finlayson. 
Smothered Country-Style Ribs

1 Tbsp olive oil
3 lbs pork ribs (I used boneless)
2 onions, finely chopped
4 cloves garlic, minced
1 tsp salt
1 tsp fresh ground pepper
1 tsp dry mustard
1 cup chili sauce
1/4 cup sugar
1/4 cup apple cider vinegar

1. Brown ribs on both sides in olive oil in frying pan.

2. Remove ribs and place them in slow cooker. Cook onions in same pan about 3 minutes or until soft. Add garlic, salt, pepper, mustard and cook and stir for 1 minute. Add chili sauce, sugar and vinegar. Bring to a boil, stirring and scraping browned bits from pan.

3. Pour sauce over ribs. Cook on low 5 hours or on high 2 1/2 hours.