- 2–2½ lb. boneless beef bottom round steaks (or braising steaks), fat-trimmed, cut into equal pieces
- ½ cup steak sauce
- 1 Tbsp. olive oil
- 4 cups (about 8 oz.) sliced mushrooms
- 1 onions, chopped
- ¼ tsp. salt
- ½ tsp. ground black pepper
- In large ziplock bag, combine steaks and sauce. Massage contents to coat evenly. Seal bag and refrigerate at least 1 hour and up to 8 hours.
- Remove steaks from marinade.
- In large skillet over medium-high heat, heat oil and add steaks and brown, turning once, about 2 minutes per side. Remove skillet from heat.
- Layer mushrooms, onions, and browned steaks in a 5-quart or larger slow cooker. Deglaze skillet with small amount of water and add pan juices to cooker. Sprinkle in salt and pepper.
- Cover. Cook on low 6-8 hours or on high 4-6 hours, or until meat is tender and cooked through.