Wash dal, add all the ingredients listed under 'Cook Toor Dal'.
Cook dal in a pressure cooker or in Instant Pot. In pressure cooker, cook for 7 hisses or whistles and then 5 minutes on low. In IP, 8 minutes on manual/pressure cook mode and natural pressure release.
This batch of toor dal took longer to cook, hence cook toor dal as you normally do.
Once pressure subsides, add cranberries, water to cooked dal and cook for 5-10 minutes or until berries are soft. Alternatively, pressure cook for one or two whistles.
Tempering
Heat oil in a saucepan, add mustard seeds, cumin and curry leaves.
When seeds pop, add onions, green chilies and saute until onions are soft.
Add garlic and let roast for few seconds.
Throw in salt, chili powder and turmeric. Mix well.
Pour the tempering over cooked dal, cover and let boil for few minutes.
Taste and adjust the seasoning.
Garnish with cilantro and serve.
Notes
Quantity of berries depends on how tart the berries are.
For a variation use moong dal.
You can cook cranberries along with toor dal. I prefer adding berries after cooking the dal to retain the shape of the berries.