Boil water in a big pot with pinch of salt. Once the water is bubbling, add clean spinach and boil it for a couple of minutes, just enough for it to wilt. Do not over boil it.
Drain the hot water out. Immediately put cooked spinach in the ice water to keep it's vibrant green color. Use fork or your fingers to wiggle it to make sure ice water goes all the way through cooked spinach lump. Once it cools down, drain all the water out and keep it aside.
Heat 1 tbsp of butter OR oil in a pan. Saute sliced onions, jalapeños, sliced garlic and ginger, white part of green onions (chopped) and cilantro stems along with 1 tsp of salt, until onions turns translucent, do not brown them.
Blend sauteed onions and spice mix, blenched spinach, cilantro leaves, green part of scallions in a blender. Blend it till it's smooth. Add just a little water if needed to get paste like consistency.
Heat ½ tsp of butter in the pan that you cooked onions in earlier. Transfer blended mix to the buttered pan. Mix well.
Rub kasoori methi between your palm to make powder (dry fenugreek leaves powder). Add that to the spinach curry and simmer it for 3-5 minutes.
Taste it and add salt if needed. Add spiced up paneer OR crispy curried tofu to the spinach curry along with 1 tsp of lime juice. Mix it gently making sure the paneer/tofu does not break! Add more water if the curry is too thick and cook it for couple more minutes.
Add 3 tbsp of heavy cream and mix gently. Skip this step if making it vegan, or sub heavy cream with cashew cream!
Serve it with any flatbread or jeera/cumin rice!