Peel and finely slice the onion. Also peel and roughly chop the potatoes, broccoli, and carrots into similar sized pieces (the smaller the pieces, the faster they'll cook).
In a pot on the hob/stove, fry off the onions until they start to turn golden brown (I use water for this, but feel free to use oil)
Add kale and cook for another 10 minutes or so, until the curry has reached your desired consistency.