Make the flatbreads. Place the flour, salt, yeast, fennel seeds and lemon zest in a large bowl. Add the oil, yoghurt and 275ml of water and mix everything thoroughly until it forms a dough. Turn out onto a lightly floured surface and knead for about 10 minutes, until soft and smooth.
(You can use a stand mixer with a dough hook for this part.) Shape the dough into a rough round and place in a lightly oiled bowl; cover with a clean cloth and leave to rise in a warm place for up to 24 hours.
When you’re ready to make the flatbreads, start the topping. Place a large, heavy-based pan over a medium heat. Add half the olive oil and when it’s hot add the garlic and sizzle for a few seconds, then add the courgettes. Season with salt and pepper.
Cook the courgettes slowly over a gentle heat, stirring regularly, for about 25 minutes or so, until they break down but still retain a little of their shape. They should be soft without colouring too much and almost spoonable in texture.
Take the pan off the heat, stir all but a handful of the herbs into the courgettes, then season again to taste with plenty of salt and pepper.
Place three baking sheets in the oven (alternatively, bake one at a time if you have limited oven space) and heat the oven to 240°C/220°C fan/475°F/gas mark 8.
Turn out the dough onto a lightly floured surface, then cut it into three equal pieces. Form each piece into a nice neat round and leave to rest for 20 minutes or so. When you’re ready to bake the flatbreads, roll out the pieces of dough. They want to be quite thin, but don’t worry if they’re not especially round, that doesn’t matter.
Take the hot baking sheets out of the oven and place a rolled-out dough on each. Spread the courgette mixture evenly over the top of each. Dot the goat’s cheese over the top of the courgette mixture and trickle all over with some of the remaining olive oil. Add the chilli flakes, if using, and a sprinkling of salt and pepper, too.
Place the trays in the oven for 12–14 minutes, or until the dough is puffed up and golden around the edges. Remove from the oven and slide onto a board. Sprinkle with a few reserved herbs and serve.