Preheat oven to 400 degrees. Cut tops off bell peppers; reserve. Discard seeds. Place peppers in a microwave-safe dish; cover with damp paper towels. Microwave at HIGH for 6 minutes. Let stand 5 minutes.
Combine 1/2 teaspoons 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 and bake at 400 degrees for 45 minutes. Sprinkle peppers with 1/4 cup parsley.
Heat a medium skillet over medium-high heat. Add oil to pan. Add onions; saute for 8 minutes, stirring occasionally. Add garlic; saute for 30 seconds. Add 1/2 teaspoons black pepper, 1/4 cup broth, tomatoes and the next 4 ingredients (water-red pepper); bring to a boil. Reduce heat; simmer 30 minutes. Stir in 1/4 cup parsley and yogurt. Serve with lemons.