Boil the Potatoes: Place the chopped potatoes in a pan and cover with cold water. Bring to a boil, then simmer for 8–10 minutes until just tender. Drain and set aside.
Toast the Spices: In a large frying pan, heat the ghee or oil over medium-high heat. Add cumin and mustard seeds and cook for 1 minute, until they begin to pop and release their aroma.
Cook the Aromatics: Lower the heat to medium. Add the diced onion and sauté for about 5 minutes, stirring occasionally, until softened. Stir in the garlic and chopped chilli and cook for another minute.
Add the Spices: Sprinkle in the turmeric, garam masala, fenugreek, and tomato purée. Stir well to coat the onion mixture with the spices and cook for 1 minute.
Combine with Potatoes: Add the drained potatoes and salt. Stir to coat the potatoes in the spiced onion mixture.
Add Stock and Spinach: Pour in the stock and add the spinach. Stir and cook for 1–2 minutes, until the spinach wilts and the mixture is heated through.
Serve: Garnish with fresh coriander and serve warm.
