Ahead of time, make the smoked yoghurt: all you need to do is to salt and hang the yoghurt in a muslin cloth placed in a sieve over a large bowl for two to three hours. Whisk in the oil, or as much as gives you that smoky flavour coming through. The recipe is easily scaled up, and keeps in the fridge for up to five days. Use the yoghurt as a dip with bread or alongside a fish dish or some lamb.
Ahead of time, make the salad dressing. Pour the vinegar into a food processor and add the mustard. With the processor working on full speed, add the oil through the feed tube. Process until the mixture fully emulsifies and the dressing is thick and creamy. Transfer to an airtight container and refrigerate until needed. Alternatively, make the dressing in a bowl: whisk the vinegar and mustard together in the bowl and add the oil, whisking all the time. The results will be less emulsified than you get in a food processor – more of a vinaigrette – and the mixture will split once you store it. Just give it a shake or a whisk again to recombine before using.
Then make the granola. Preheat the oven to 180°C/160°C fan/Gas Mark 4. Place all the dry granola ingredients in a mixing bowl. In another bowl, whisk together the oil, and the agave and maple syrups. Pour the wet mixture over the oat mixture and mix well until everything is coated evenly. Spread the mixture on a tray lined with baking paper and bake for 10 minutes. Remove from the oven, give everything a stir and return to the oven to bake for another 10 minutes, or until golden and crisp. Remove from the oven and allow to cool. (You can store the granola in an airtight container in a cool, dry place for up to five days, if you like.)
Make the salt dough for the baked vegetables. Mix the flour and salt together in a large bowl. Add the egg whites and 190ml of water. Stir with a spatula to form a firm dough, adding a little more water, if needed. Using your hands, knead the dough for a couple of minutes until smooth. Wrap the dough in cling-film and refrigerate for 30 minutes, or until needed.
Preheat the oven to 200°C/180°C fan/Gas Mark 6.
Turn out the dough onto a lightly floured work surface. Using a rolling pin, roll out the dough until large enough to create a piece that will wrap fully around the four beetroots in one parcel and around the four turnips in another parcel. The dough is very pliable, so feel free to use your hands to push it around the vegetables. Place both parcels on a lined baking tray and bake for 30–40 minutes for the turnips and 45–60 minutes for the beetroots, depending on the size, until tender, then remove from the oven and leave to cool. (To check the vegetables during the process, stick a knife in through the dough casing to check firmness – the vegetables should yield to the knife when they are ready.)
When cooled, break open the salt crusts and peel away the skins of both the beetroot and turnips. Roughly chop up the cooked vegetables, and set aside in separate bowls.
To serve, spread some smoked yoghurt over each plate. Sprinkle the turnip and beetroot with a little rapeseed oil, then spoon equal amounts of each on to the bed of yoghurt. Cut the pickled walnuts into four and add the slices to each plate. Sprinkle over the walnut granola. Toss the turnip and beetroot tops in the dressing and use these to finish each plate.