Turkish Testi Kebab

Name: Turkish Testi Kebab
Cuisine: Middle Eastern
Ingredients: 500g lamb or beef, cubed; 1 large onion, diced; 2 medium tomatoes, chopped; 1 medium green bell pepper, chopped; 1 medium red bell pepper, chopped; 2 cloves garlic, minced; 1/2 cup mushrooms, sliced; 1/2 cup olive oil; 1 tsp ground cumin; 1/2 tsp ground black pepper; 1/2 tsp red pepper flakes (optional, for extra spice); Salt to taste; 1 cup beef or vegetable broth; Fresh parsley, chopped, for garnish; Clay or ceramic pot (traditionally used in Testi Kebab preparation)