Lentils with spices and arugula

This came about through a need to eat more veg, but also to act as a refreshing side dish to the creamy, rich lamb korma I served with it. I improvised the usual recipe for saag aloo, which I've made many times, resulting in a fairly spicy, bitter and savoury dish.

Recipe : Lentils with Indian spices and arugula

1 tbsp oil or ghee
2 tsp butter
1/2 onion, peeled and thinly sliced
1/2 bell pepper, seeded and finely sliced
1 clove garlic, peeled and thinly sliced
1 inch piece of ginger, peeled and finely chopped
1 green chili pepper, seeded and finely sliced
3 green cardamon pods
3 cloves
1 tsp chili powder
1/4 tsp turmeric
1 can of green lentils, drianed of all the liquid and refreshed with cold water several times
a handful of arugula
5 cherry tomatoes, halved
1/2 tsp salt (or more to taste)
juice of one lemon

Heat the oil or ghee and butter in a frying pan over medium heat and saute the onion, garlic, ginger, chili pepper, bell pepper, cardamoms and cloves until fragrant and slightly softened, (about 7 minutes), stirring frequently. 

Add the chili powder and turmeric and stir well, cook gently for 1 minute. 

Add the lentils, arugula, tomatoes and salt and stir well. Reduce the heat to low and let it all gently fry until the arugula is wilted, the tomatoes slightly softened and the lentils heated through. Squeeze over the lemon juice and serve.