1. Preheat the oven to 350°. Spread the walnuts in a pie plate and toast in the oven for 8 minutes, until fragrant. Let cool.
2. In a large, deep skillet, heat the olive oil until shimmering. Season the chicken thighs with salt and pepper and cook over moderately high heat, turning once, until lightly browned on both sides, about 8 minutes total. Transfer the chicken to a plate. Add the onion, garlic and ginger to the skillet and cook over moderate heat until tender, about 6 minutes. Stir in the broth, scraping up the browned bits from the bottom of the skillet. Add the cumin and saffron.
3. Return the chicken with any juices to the skillet and bring to a simmer. Cover and cook over low heat until the chicken is tender and cooked through, about 30 minutes. Transfer the chicken to shallow bowls. Season the broth with salt and pepper and spoon it over the chicken. Sprinkle with the walnuts and cilantro and serve.