Spray a 6-quart or larger slow cooker with cooking spray.
Add vegetable oil to a large skillet and heat over medium heat. Season the ribs with salt and pepper. Add the ribs to the pan and sear until lightly browned on all sides, working in batches if necessary. Transfer the ribs to the slow cooker.
2 tablespoons vegetable oil, 2½ - 3 pounds boneless country style pork ribs, 1 teaspoon salt, ½ teaspoon ground black pepper
Drain the oil out of the skillet then melt the butter over medium heat. Add the chopped bell pepper and onion and sauté until softened. Add the minced garlic and cook for 1 additional minute, stirring frequently so it doesn't burn. Remove from heat.
2 tablespoons butter, 1 green bell pepper, ½ cup yellow onion, 1 teaspoon garlic
Add the tomato sauce, diced tomatoes, barbecue sauce, brown sugar, and vinegar to the skillet and mix until combined. Pour the sauce over the ribs in the slow cooker.
1 (29 oz) can tomato sauce, 1 (28 oz) can diced tomatoes, 1 cup barbecue sauce, ¼ cup light brown sugar, 3 tablespoons white vinegar
Cover and cook on low for 6 to 8 hours (recommended) or high for 3 to 4 hours; the meat should be tender when done. Be sure the internal temperature reaches at least 145°F to safely serve, however, we highly recommend aiming for 190°F, this helps break down the connective tissue for super tender fall-apart meat.
Chop the ribs into small pieces, then serve over mashed potatoes or rice. Smother with the tomato sauce from the crockpot and add freshly chopped parsley.
Chopped parsley for garnish