- STEP 1
Heat the oil over a medium heat in a large saucepan. Add the mustard seeds and cook them until they start to pop and crackle. (TIP: Because the next step is very loud and 'hissy' you can use the lid of the saucepan to shield yourself from any hot oil spurts). Add the contents of the chopped tomatoes into the pan and stir until the hissing stops.
- STEP 2
Half fill the empty tomato tin with water and pour into the saucepan. Stir and cook the tomatoes for a little while. Add the garlic and ginger paste, coriander, cumin, turmeric, salt and pepper. Stir it all up and cook for about 4 or 5 minutes.
- STEP 3
Add the mushrooms, spinach and cooked potatoes to the saucepan. Stir well. Cook uncovered until the sauce begins to boil, then cover with the lid and reduce the heat to low simmer. Cook until the spinach has completely drooped and the mushrooms are cooked through, stirring occasionally -- about 15 - 20 minutes, sometimes more.
- STEP 4
Serve with hot basmati rice and, depending on your preference, top with fresh coriander leaves.