Put your oil or ghee in a large pot. Add the onions and cook them over medium heat until they are just beginning to turn golden.
Potatoes, a green chili, ginger, garlic, and spices should all be added. Give these a short 3-minute sauté while frequently stirring.
Add your diced tomatoes as well as 1/2 cup of water. Then, cover and simmer for 10 minutes after bringing to a boil.
The chopped spinach should be added. Cook this on low heat with a lid on for five minutes, then remove the top and continue cooking until all of the water from the spinach has been cooked out. To prevent the potatoes from breaking, swirl the saucepan rather than stirring it, as described in the recipe page.
When the curry is done cooking, add the dried fenugreek. There is no need to boil the fenugreek.