Saute the onions in 2 tablespoons of the clarified butter over medium-low heat until light golden brown. Add cumin, ground red chile, and coriander and mix it thoroughly. At any point, you may add more clarified butter if the sauce becomes too thick, but be cautious, because this recipe can easily become extremely rich. Add the ginger paste and garlic paste and cook for a few minutes. Add the red chile paste and cook for a few additional minutes, then the cashew paste and tomato puree. Cook over low heat, stirring, until thick. Set aside or refrigerate until ready to add chicken.