1. Whisk together first 2 ingredients until smooth.
2. Sprinkle beef with flour, salt, and pepper; toss to coat.
3. Cook beef, in batches, in hot oil in a large skillet over medium-high heat, stirring occasionally, 10 to 12 minutes or until browned. Place in a 6-qt. slow cooker. Add sweet potatoes, next 8 ingredients, and broth mixture. Cover and cook on HIGH 6 to 7 hours or until tender.