Trim fat from roast. Cut roast into 1-inch pieces. In a large skillet brown meat, half at a time, in hot oil over medium-high heat. Drain off fat. Transfer meat to a 3 1/2- to 4 1/2-quart slow cooker. Stir in broth, water chestnuts, sweet pepper, soy sauce, hoisin sauce, ginger, crushed red pepper, and garlic.
Cover and cook on low-heat setting for 7 to 8 hours or on high-heat setting for 3 1/2 to 4 hours. Skim off fat. Stir in edamame and ramen noodles (reserve seasoning packet for another use). Cover and cook for 5 minutes more. Top each serving with sliced green onions.
If desired, replace ramen with 6 ounces fresh noodles and add a poached egg to the soup.