In a large bowl, mix the chicken with yogurt, onion, ginger, garlic, garam masala, turmeric powder, salt and pepper. Leave in the fridge to marinate for 6 hours.
Meanwhile dissolve ground saffron in 1/4 cup of boiling water and set aside (click for How to Use Saffron).
Place the chicken and its marinade in a pot. Add the grated tomatoes, ground almonds, cilantro and mint.
Cook over medium heat for 20 minutes. Then add the baby potatoes and dissolved saffron. Continue to cook covered until chicken and potatoes cooked through and to desired thickness, stirring occasionally. Serve the stew with bread or rice.