Place couscous in a large bowl. Bruise the cardamon. Add to bowl with salt and butter. Pour over about 850ml boiling water. Stir once and leave to stand for 10-15 mins.
Toast almonds and pine nuts in a dry pan until golden.
Chop the pistachios. Once couscous has absorbed all the liquid, add the nuts and mix through with a fork. Check the seasoning and serve at room temperature.