Begin by making the spice mix: toast the peanuts for a minute or 2 over medium heat. Add the coriander seeds. Toast, shaking occasionally, until they start to get fragrant. Add the the cumin seeds and continue toasting and shaking the pan until fragrant and darkened, but not burned. Transfer to a small bowl to let cool.
When the spices and peanuts have cooled, transfer to a spice grinder and grind until they are a fine powder. Set aside.
Preheat the oven to 300 F.
Heat the oil in a large Dutch oven over medium high heat. Add the beef, in batches so as to not overcrowd the pan, and brown on all sides. Remove the browned beef, using tongs or a slotted spoon, to a bowl.
Immediately add the onions with a pinch of salt. Place a cup of water beside the cooktop. Add a splash of water if the onions do not produce enough liquid to deglaze the pan.
Scrape the bottom of the pan to remove the browned bits. Caramelize the onions, stirring occasionally, splashing a little water into the pot if the onions start to scorch or stick.
When the onions are golden, add the ginger and garlic with a pinch of coarse aleppo. Keep stirring and splashing water as needed, until the onions are dark golden brown.
Add the spice mix and stir. Cook for 1 minute, stirring.
Add the chopped tomatoes with juices. Stir and scrape up any bits that have stuck to the bottom of the pan. Cook for 5 minutes.
Mix in the 3 cups of water and the ground peanuts. Add the beef chunks with any accumulated juices in the bowl. Make sure they are covered by liquid. Bring to a boil. Place a heavy, tight-fitting lid on the pot, and place in the oven.
Cook for 2 hours.
Remove the pot from the oven and place on a burner on low heat. Add the tamarind and brown sugar. Stir. Then add the potatoes and stir. Replace the lid and put back in the oven.
Cook for another hour. Check the beef and potatoes both for doneness--if either is not yet fork tender, put it back in the oven, still covered, and cook for another 30 minutes. Repeat test.
When the potatoes and beef are tender, taste for additional salt.
Serve with a sweet and sour chutney. If serving with Basmati rice see note below.
*If you prefer to serve with rice, reduce the potatoes to 3, cut them smaller, and serve with Basmati rice