Kale and potato curry

SOURCE This recipe comes from Nathan Chantrell. We have made some of the recipe steps more explicit for the novice cook.
Serves 2. Portion sizes ideal for lunch. Add side helpings of meat or other vegetable dishes for a more substantial meal.
Time (approx): preparation 20m cooking 40m

150g kale leaves*
500g potatoes*
200g onion*
2 garlic cloves
2cm piece ginger
1 mild chilli
2 cardamom pods
1/4 tsp garlic powder
1/4 tsp garam masala
1/2 tsp MUSTARD seeds
1/2 tsp ground cumin
1/2 tsp ground coriander
1/4 tsp ground turmeric
Olive or vegetable oil
* Prepared weight
Knife with a sharp blade
Plastic or wooden spoon or spatula for stirring
Vegetable peeler
Mortar and pestle (optional)
Large saucepan
Measuring jug.
A hob or other direct heat source for cooking; Space to prepare ingredients.
Advance preparation
None required.
Preparing the Vegetables
Remove the kale leaves from the stalks and roughly shred them.
Peel the potatoes and cut into 2.5cm dice.
Peel the onion(s); cut in half, cut each half into thin slices.
Peel the garlic cloves and chop them roughly; peel and chop the ginger; chop the chilli finely.
Mash these three ingredients with the mortar and pestle, together with a pinch of salt. (If you don’t have a mortar and pestle, crush with a clean glass jar in a small bowl.)
Crush the cardamom pods.
Cooking the meal
Heat the oil in the pan, add the onion and garlic powder and cook on a low heat until onion is soft and translucent.
Add the mashed garlic/ginger/chilli to the pan and cook for a few minutes.
Add the cardamom pods and the remaining spices to the pan and cook for another minute.
Add the potatoes and 2 tablespoons of water and cook for 5 minutes, continually stirring to make sure the potatoes are coated in the spices.
Add 250ml of water, bring to the boil, then cover and simmer for 10–15 minutes or until the potato is cooked.
Add the kale and and some hot water if there is not enough remaining to cook the kale; simmer for 3–4 minutes until the kale is tender.
Suggested accompaniment
The curry would be very nicely complemented by a good-quality chutney. As noted at the start, it can become a main meal by the addition of other meat or vegetable dishes to the side.