Potato and chickpea curry with peanuts and garlic

This marks my first successful attempt to improvise a dish based on Indian cuisine — I'm pretty comfortable with Mediterranean, Latin American, Chinese and Japanese flavors and ingredients, but until now whenever I've strayed from recipes in making curries and dals and so forth, the results have not been so good. This, however, even my 10-year-old daughter liked.

This is based loosely on this recipe from Raghavan Iyer, but heavily adapted to what I had on hand.

2-3 medium red potatoes
1 to 1 1/2 cups cooked chickpeas (or one can, rinsed well)
a good handful of peanuts
2-3 garlic cloves, peeled and roughly chopped
1 small chile pepper, minced (remove seeds if you don't like it too spicy)
1/4 tsp turmeric
good handful of cilantro
1 medium onion, chopped
canola or other neutral oil for cooking
salt & pepper to taste

1. Cut potatoes into 1/2" chunks and cook in boiling salted water until just tender (5-10 minutes). Reserve about a cup of the cooking water, then drain.
2. Remove the leaves from the stems of the cilantro; reserve leaves but chop stems roughly.
3. In food processor or mortar and pestle, whiz up or smash the peanuts, garlic, chile pepper, turmeric and cilantro stems with a pinch of salt until a paste forms.
4. Heat a little oil in a large skillet. Add onions and cook until starting to brown. Add peanut-garlic paste and cook, breaking up the paste and stirring contantly, for about a minute or two (you don't want to garlic to burn or it will get bitter)
5. Add the potatoes, chickpeas, and a good bit of the reserved potato cooking water. Reduce heat and cook, covered, for 10-15 minutes to allow flavors to blend, adding more potato water (or tap water if you run out) as necessary to keep it from drying out.
6. Serve over hot rice or with dosas (as shown here; I use this recipe, though I substitute regular green lentils for the urad dal), garnished with the reserved cilantro leaves, roughly chopped.