1. Combine chicken, onion, garlic, cumin, coriander, turmeric, chili powder, salt, and black pepper in a large bowl. Mix well to coat the chicken evenly.

2. Heat 15ml or 1 tablespoon of oil in a large skillet over medium heat, approximately 180°C or 350°F. Add the chicken mixture and cook until browned, about 5-6 minutes. Remove from heat and set aside.

3. In the same skillet, heat another 15ml or 1 tablespoon of oil. Add the cumin seeds and let them sizzle for a few seconds.

4. Add 250ml or 1 cup of chicken broth and 120ml or 1/2 cup of heavy cream to the skillet. Bring the mixture to a boil, then reduce the heat to low, approximately 80°C or 176°F, and simmer for 10 minutes.

5. Stir in 60g or 1/4 cup of yogurt, 2 teaspoons of garam masala powder, 15g or 1/4 cup of chopped cilantro, and 15g or 1/4 cup of chopped mint. Cook for an additional 2 minutes.

6. Add the cooked chicken back to the skillet and simmer for 5 minutes, until heated through.

7. Prepare the cold yogurt sauce by combining 60g or 1/2 cup of grated cucumber, 120g or 1/2 cup of yogurt, 7g or 1 tablespoon of dried mint, and a pinch of salt in a bowl. Mix well and refrigerate until serving.

8. Serve the chicken korma hot, with the cold yogurt sauce on the side. Garnish with additional cilantro and mint if desired.