Heidi's version at 101 cookbooks (this is a half batch- served 2 for a big dinner). The preparation takes the most time, then the curry itself goes together quickly (20 minutes?)
Wash and finely chop 0.5 - .75 lb baby spinach. This is about half of a huge 1 lb box from Costco (i.e. earthbound farms' spinach). Set aside in a bowl.
Chop 1 yellow onion into small dice. Smash 3 cloves garlic. Grate 1 TB of ginger.
Cut approx 8 oz paneer into cubes (Costco sells in 2 packs or buy at an indian grocer. Paneer freezes nicely so you can reserve the extra).
Grind in mortar and pestle the spice mix:
2 TB cumin seeds
1 TB corriander seeds
2 tea mustard seeds
1 tea red pepper flakes
1/8 tea cardamom
Fry up the paneer in olive oil or butter until starting to brown. Use a spatula carefully when turning the paneer so you don't leave all the browned bits in the pan. Turn out browned paneer onto a plate.
Add a little more oil or butter to the pan. Saute diced onion until browning. Stir in 1/2 tea salt.
Add garlic, ginger, 1 TB of ground spices from above and 1/4 tea turmeric. Cook for 60 seconds until it releases some aroma.
Add all of the chopped spinach and stir a little to coat. Cook for 5 minutes or until the spinach is cooked down quite a bit but not scorched.
Finally add 1/2 C buttermilk, 1/4 - 1/2 tea amchoor powder (dried mango powder, or substitute some fresh lemon juice). Toss in the browned paneer and stir to combine.
Serve over brown rice, or with naan or chapati bread.