heat the oil in a karai or frying pan on medium heat to below the smoking point
drop in a couple of cumin seeds. If they sizzle immediately add the rest together with the blade of mace
let the spices release their aroma for 15-20 seconds taking care they don't burn
add in the fresh chillies. Toss for 10 seconds
finally add the hing, let it sizzle for just a few seconds and immediately add in the onions to stop the spices from browning
when the onions are translucent add the garlic, cook for a minute
now add the powdered spices, mixing them in with the onions and oil, and finally add the curry gravy (or tomato) and salt to your taste
if you're using nutmeg rather than mace add it now
simmer until the spinach is fully defrosted and cooked and most of the liquid has evaporated, adding a splash of water as needed to prevent sticking
serve with a small dollop of yoghurt