Preparation

• Pour some cold water into a bowl or salad spinner and add the lemon juice, ready for the fennel.
• Trim the very bottom off each fennel bulb, and leave on enough of the top green stalks to use as handles. Using a mandoline or sharp knife, shave the fennel very thinly, in the same direction as the ribs run. Pop the fennel shavings into the bowl or salad spinner, along with the fennel and dill fronds. If using the beetroot and/or radish, shave these thinly and add to the bowl or spinner, too. Leave in the fridge to get super crunchy, crisp and cold while you get on with the rest of the salad.
• To make the smoky spring onion oil, cut the green tops off the spring onions and reserve. Slice the spring onion whites into thin ribbons, about 3 cm (1¼ inches) long, then pop in the bowl in the fridge with the fennel to curl up.
• Toss the green spring onion tops in a heavy-based pan and heat over high heat for 3–4 minutes until they turn a brighter green, with flecks of gold and black. While still hot, use tongs to add them to a small blender with the dill stems, chives, grapeseed oil, salt and sugar, if using. Blitz for 2–3 minutes to a bright green mush; the heat generated by the blender blades will help to extract the green colour and the flavour of the herbs.
• Drape a piece of muslin (cheesecloth) over a strainer and place over a bowl. Pour the spring onion mixture into the strainer. Leave the oil to drip through on its own, which should take about 20 minutes. Pour the strained oil into a squeeze bottle or small pouring jug and set aside for serving.
• Meanwhile, zest the oranges and grapefruit, reserving the zest, then segment the fruit. Squeeze the left-over citrus peels and membranes into a small jar to extract any remaining juice. Add all the chive vinaigrette ingredients and the reserved zest, seal the jar and shake vigorously to help them get friendly, to the point of emulsification.
• Drain the chilled shaved fennel mixture and spring onion curls and spin until fully dry.
• Toss the fennel mixture in the vinaigrette and place in a serving bowl. Garnish with the citrus segments and spring onion curls. Serve drizzled with the smoky spring onion oil.