Oil and season the wedges of squash and roast in a 200°C pre-heated oven until browned and tender, about 20-25 minutes. Repeat with the onions. Remove, cool and process into separate purées. Slice, oil and season thin slices of your chosen Mediterranean vegetables and roast until caramelised and tender, about 20-25 minutes. Mix the flour, baking powder, yoghurt and salt in a bowl or pulse in a processor until just coming together. Tip onto a clean board and briefly knead into a dough. Chill for five minutes. Cut into four pieces and then divide each into three balls. Roll out, well-floured on each side, to a few millimetres thick and to about 10cm diameter. Heat up your griddle pan or wood-fired oven until very hot, wipe your bars or griddle pan with oiled kitchen paper, lay dough pieces on and then cook for a minute or two on each side, until just set and puffy (but not too coloured), turning with tongs. Keep warm and repeat.
Pre-heat your oven to 220°C. Spread a thin layer of the squash onto the breads (leaving a 3cm margin), top with the roasted vegetable slices and brush the bread edges with clarified butter. Bake for 5-7 minutes until browned and bubbling. Meanwhile crumble the cheese and loosen with a little yoghurt and seasoning. Halve the radishes and with a knife or mandolin, carefully slice the beetroot as fine as possible. Garnish the cooked flatbreads with small dollops of onion purée, cheese mixture, radishes and beetroot. Top with the herbs and leaves and a drizzle of oil.