Chickpeas and Greens

This recipe is from Ottolenghi's cookbook Plenty, but with a couple of variations.  I had collard greens from my CSA, which require long cooking to become tender whereas his recipe calls for Swiss Chard, which cooks up quickly.  He called for tamarind and I subbed apple cider vinegar.

• 1 lb swiss chard (stalks and leaves), cut into 3/8-inch slices, or other greens
• 1 medium onion, thinly sliced
• 1 tbsp olive oil
• 14 oz canned chopped plum tomatoes, with their juices
• 1 1/2 tbsp sugar
• 1 cup dried chickpeas, soaked and boiled (or 2 cans chickpeas)
• 1 1/2 tsp coriander
• 3 tbsp tamarind paste or apple cider vinegar
• salt and black pepper
• 2 lemons
• cilantro
• greek yogurt

1. Put the onion and olive oil in a large heavy pan and saute on medium heat for about 10 minutes, or until the onion is soft and golden.   Add the canned tomatoes, sugar, chickpeas, ground coriander, chard or other greens that have been cooked until tender, and some salt and pepper. Add water to keep the texture desired.
2. Add the tamarind.  Bring to a boil, then cover with a lid and leave to simmer for about 20 minutes.  Taste and add more salt and pepper if needed. Add the juice of two lemons just before serving.
3. While the stew is cooking, chop cilantro for serving.
4. When ready to serve, spoon in to bowl and can finish with greek yogurt and cilantro.