Tip the carrots and fennel into a salad bowl. Toast the nuts
in a hot frying pan for 3-5 mins until golden, then tip onto a plate.
In the same pan, heat the oil and fry the mustard and nigella or black
onion seeds, if using, until they begin to pop – about 30 secs. Pour
in the lemon or lime juice and mix together to make a dressing.
Toss together with the vegetables in the bowl, then sprinkle
with nuts to serve.