Slice fennel bulb into thin rounds (if you have one, use a mandoline on the second setting).

Heat olive oil in a small frying pan, and when hot (not smoking) add the fennel. (If the oil starts to smoke throw it away and start again since the oil burns and becomes harmful.) Stir fry gently on a medium heat, with a pinch of salt, until is starts to soften and some of the edges start to brown but it still retains a bit of crunch. Turn off heat and place fennel into a bowl.

Cut off a quarter of the grapefruit and remove the pith with a sharp knife until only the flesh is left. Then make thin slices, in any direction that works.

Mix grapefruit with the cooked fennel. Take a few coriander leaves and either chop or tear them and add to salad. Add a tiny pinch of salt and a small drizzle of olive oil if needed.

Leaving it to sit for a few minutes will allow the flavours to meld and improve the overall taste. This can be made ahead and refrigerated.