Add the kale to a large bowl, add the juice of half a lemon, half a teaspoon of sea salt and 1 tablespoon of extra virgin olive oil. Rub the lemon juice oil mixture into the kale leaves for about 2 minutes then set aside for 3o minutes.
Place the beetroot and sweet potato on a baking tray, add 1 tablespoon of olive oil, a pinch of sea salt and a little freshly ground black pepper give the tray a shake and place in a pre heated oven for about 25 minutes or until the vegetables are cooked.
Cook your quinoa and make the dressing. To make the dressing add the lemon juice and mustard to a small bowl and mix, then slowly add the extra virgin olive oil, whisking all the time. Season with sea salt and freshly ground black pepper.
When the quinoa is cooked, allow it to cool a little then add it to a large serving bowl with the kale. Add the sweet potato, beetroot and chopped onion, mix gently then serve with some crumbled feta if using and the mustard dressing.