Peal the oranges and cut up into 2cm chunks.
Slice the bulb of fennel in half and cut the base off. Use a mandolin to thinly slice it up and add to a bowl with the orange pieces, and any juice.
Drizzle over some good quality olive oil and add a good grind of salt and pepper.
Toss everything well and garnish with some of the feathery fennel fronds if you had any on the bulb.