In the same large saucepan, heat the 2 tablespoons of oil. Add the cumin seeds and cook over moderately high heat until fragrant. Add the garlic and 2 tablespoons of the ginger and cook over moderately high heat until the garlic is golden. Add the yogurt, cayenne pepper, and the 1 cup of water and simmer over low heat, stirring occasionally, for 5 minutes. Add the cranberries, pistachios, and garam masala and simmer for 5 minutes, stirring occasionally. Season to taste with salt.