1.Rinse split peas under cold water until water runs clear; drain.
2.Heat ghee in large frying pan; cook onion, garlic, ginger and chilli, stirring, until onion softens. Add seeds and spices; cook, stirring, until fragrant. Transfer onion mixture to 4.5-litre (18-cup) slow cooker; stir in undrained tomatoes, stock, water, sugar and split peas. Cook, covered, on low, 10 hours.
3.Add in silver beet, stir until wilted; season to taste.