Add yellow split peas to a large saucepan with half the garlic, tomato, salt and chilli if using. Add 6 cups water and bring to the boil. Skim off any froth that forms on the surface, this will stop it boiling over.
Continue boiling, adding an extra 4 cups of water as the liquid absorbs, for 45 minutes or until the split peas are tender and falling apart. Stir often to ensure if doesn't stick.
Once the dhal is cooked add oil to a large saucepan or pan and fry the onion until tender, add garlic and spices and continue to fry until just browned.
Add the split peas to the fried onion, being careful it doesn't splatter. Stir to combine. Turn off heat and add butter if using, combine well. Adjust seasoning.
Serve with rice, natural yoghurt, fresh coriander, hemp seeds and sweet chutney - or simply on its own.