In a 3-1/2- or 4-quart slow cooker combine broth, carrots, bamboo shoots, water chestnuts, the 1/2 cup water, the mushrooms, vinegar, soy sauce, sugar, and crushed red pepper.
Cover and cook on low-heat setting for 6 to 8 hours or on high-heat setting for 3 to 4 hours.
If using low-heat setting, turn to high-heat setting. In a small bowl stir together cornstarch and the 2 tablespoons cold water.
Stir into chicken broth mixture in slow cooker.
Add frozen shrimp and the tofu.
Cover and cook for 30 minutes more.
Sprinkle each serving with parsley.