1. Preheat oven to 400°.
2. Cut tops off bell peppers; reserve. Discard seeds. Place peppers in a microwave-safe baking dish; cover with damp paper towels. Microwave at HIGH 6 minutes. Let stand 5 minutes.
3. Combine 1/2 teaspoon black pepper, 1/4 cup broth, and next 5 ingredients. Divide beef mixture among peppers; top with tops. Pour 2 cups water into dish; cover. Bake at 400° for 45 minutes. Sprinkle peppers with 1/4 cup parsley.
4. Heat a medium skillet over medium-high heat. Add oil to pan. Add onion; sauté for 8 minutes, stirring occasionally. Add garlic; sauté for 30 seconds. Add 1/2 teaspoon black pepper, 1/4 cup broth, tomatoes, and the next 4 ingredients; bring to a boil. Reduce heat; simmer 30 minutes. Stir in 1/4 cup parsley and yogurt. Serve with lemons.