Red lentil dhal

rice, for four

400g red lentils

2 tsp ground turmeric

generous knob of butter

dash of rapeseed oil

1 small onion, finely chopped

4 garlic cloves, finely chopped

1 red chilli, finely sliced

thumb size piece of ginger, grated

2 ripe tomatoes, finely chopped

2 tsp cumin seeds, toasted

1 tsp ground coriander

handful of coriander, chopped