Sometimes I think my best dinners result in the hardest to write recipes. You know, me standing at the stove with 8 billion herbs, spices and aromatics beside me, tasting and tossing into the pot without regard for amount as it cooks. That is completely what happened here. The good news is, that means it is not rocket science–it is just made to taste. So I have done my best with amounts, but be sure to taste the dish periodically toward the end.
So this stew. It was fantastic. I could have licked my bowl. It is not sour like pucker your lips lemon sour, but rather more the earthy sour of amchur with the deeper, less puckery sour notes from the yogurt. So do not be frightened by the name! It is important to mix the yogurt in and serve immediately–but this stew makes a ton, so I suggest mixing a 2-4 tablespoon dollop of yogurt into each individual serving, so the leftovers can be brought to a boil without mellowing that yogurt taste (or you could just cut the recipe in half). This is what we did and it is why I am unsure of the final amount of yogurt needed. If you are serving the stew on a more formal occasion, just mix yogurt into the pot by the half-cup-ful, tasting as you go.
1-2 T vegetable oil
1 T ghee
2 t dark mustard seeds
2 t cumin seeds
4 medium-large red onions, thinly sliced
1 t paprika or cayenne
1 t turmeric
cup of water by stove, as needed
1 head of garlic, minced
1 T amchur powder
1 T ground coriander
1 T ground cumin
2 large sweet potatoes, peeled and cubed
6 medium-large all purpose yellow (like Yukon Gold) potatoes, peeled and cubed
water to cover the cubed potatoes (reserve the water when draining)
8 medium-small tomatoes, pureed with 1 cup water
1 cup red lentils
2 t garam masala
amchur (if needed) to taste
1 T cornstarch dissolved in 1 T cold water
1 lb frozen peas
juice of 2 limes or lemons (taste after 1)
salt to taste
Greek or Indian style yogurt, low fat or, even better, full fat–see notes above
tamarind chutney or some other sweet/sour chutney
cilantro (I was out and we are snowed in)
cayenne pepper or red pepper flakes for increasing the heat
Heat the oil and ghee in a large soup pot or Dutch oven. Add the mustard seeds and fry until they finish popping. Add the cumin seeds and toss with the mustard seeds. They will darken and become fragrant in about 15-30 seconds–do not let them burn. When they are darker, add the onions with a pinch of salt. Fry the onions, stirring occasionally, until they are quite caramelized. Keep a cup of water by the stove so that if they start to stick and burn you can add some water to the pan and deglaze.
When they are brown and quite soft, add the paprika/cayenne and turmeric. Stir to evenly distribute the spices and keep caramelizing until the onions are dark brown. Add the cumin, coriander, amchur and garlic and mix in thoroughly. Cook for 1 minute. Add the (drained) potatoes and toss them to distribute the spice evenly. Fry for 1-2 minutes, then add the lentils and the potato soaking water and the pureed tomatoes. Add a hefty pinch of salt, to taste (remember there is no stock in this stew so it will definitely need salt).
Bring to a boil and let the stew briskly simmer, uncovered, until the potatoes are tender but not falling apart. Add the dissolve cornstarch and peas and bring back to a boil for 1 minute. Then add the garam masala and the juice of 1 lime/lemon. Taste for more amchur, lemon/lime juice or salt. The stew should taste good but not amazing–the yogurt is what really makes it.
Mix with the yogurt, either in the pot or the bowl (see comments above), and sprinkle with cilantro. Add lime wedges and more cayenne pepper if desired. I highly recommend a sweet/sour chutney like tamarind as well.