Dust chicken pieces wiht flour, shaking to remove excess flour. In pressure cooker, heat oil. Add chicken and saute in hot oil until browned, turning. Transfer chicken to a platter and reserve. Add green onions, garlic, and parsley and saute in hot oil 2 minutes.
Add chicken and stir. Sprinkle with spearmint and cumin. Add broth, lemon juice, yogurt, salt, and pepper. Stir well. Secure lid. Over high heat, develop steam to high pressure. Reduce heat to maintain pressure and cook 10 mins. Release pressure according to manufacturer's directions.
Remove lid. Place chicken in serving dish. Ladle out 1/2 cup of hot broth and whisk into egg yolks. Add flour or potato starch to yolk mixture. Stir into cooking liquid. Cook, stirring, until thickened. Serve with steamed rice and vegetables. Serves 6.