Heat 1 tablespoon of the butter and sauté cashew nuts until golden brown. Set aside.
Heat remaining 4 tablespoons of butter and fry mustard seeds until they pop.
Add onion, crushed red pepper and coriander leaves. Fry until onion is golden.
Add salt and farina. Stir until farina is very hot.
Pour in boiling water, stir cover and cook over moderate heat until water is absorbed.
Stir in the sautéed cashew nuts.
Fresh lime juice can be sprinkled over individual serving, if desired.