Preheat the oven to 200°C/180°C Fan/Gas Mark 6.
First, make the aubergine purée. Wrap the aubergine in foil and bake it in the
oven for 35–40 minutes until completely soft, then halve it lengthways and scoop out the flesh.
Put the flesh in a blender with the tahini, yoghurt and garlic and blitz until smooth. Pass through a fine sieve and season with a pinch of salt.
While the aubergine is cooking, make the radish sauce. Warm the oil in a medium, heavy-based saucepan over a medium heat, add the shallot and sweat for 5–6 minutes, or until translucent, stirring regularly.
Add the mushrooms and sweat for a further 3 minutes, or until soft and tender. Stir in the tomato purée and cook for 3–4 minutes. Add the radishes and vegetable stock and bring to the boil. Reduce
the heat and simmer for 8 minutes. Remove from the heat and blitz with a hand-held blender until smooth, then strain through a fine sieve. Finish the sauce
by seasoning with sherry vinegar and salt and whisking in the butter.
Reduce the oven temperature to 160°C/140°C Fan/Gas Mark 2.
To make the granola, warm the honey, oils and 1 teaspoon of salt in a small saucepan over a low heat until the honey has melted and the salt dissolved.
Mix in the oats. Transfer to a baking tray spread it out in an even layer and bake for 15 minutes, or until golden. Remove from the oven and leave to cool, then break into small pieces. Leave the oven at the same temperature.
Put the radishes on a baking tray, chopping any larger ones in half, season with a pinch of salt, drizzle over half the oil and roast for 10–12 minutes.
Heat the remaining oil in a medium, non-stick saucepan and add the rhubarb chard leaves along with a splash of water. Cook gently until the leaves have wilted and season with a little salt.
Warm the radish sauce. Put a spoon of the purée in the centre of four plates and place the roasted radishes on top. Add the chard, purslane leaves and flowers.
Spoon the sauce around the outside and sprinkle with truffle granola. Drizzle with rapeseed oil.