These slow cooker beef short ribs are fail-proof and fall-off-the-bone. A low and slow 9-hour hands-off cook time yields tender, juicy, flavorful meat along with veggies and a tangy braise.
Put flour, salt, and pepper in a large Ziploc bag. Add ribs and shake to coat.
Melt butter in a large skillet over medium heat. Place ribs in the skillet; increase to medium-high heat; brown each side for 30-45 seconds. Do it in batches if necessary.
Transfer the ribs to the slow cooker. Add mushrooms and bell peppers.
In the same skillet, combine onion, broth, vinegar, sugar, chili sauce, ketchup, Worcestershire sauce, minced garlic, chili powder, and the remaining flour from the bag.
Bring to a boil; stir well.
Pour over ribs. Cover and cook on low for 9 hours.