Bake the onions
Heat your oven to 150°C. Line a large oven tray with baking paper. Combine the honey,vinegar and 1 tbsp of the oil in a bowl and season with salt.
Add the onions and toss to coat. Pour the mixture onto the tray and place in the oven for one hour,turning halfway through. Remove from the oven and allow to cool.
Increase the oven temperature to 250°C.
For the dough,mix the dry ingredients together until combined,then add ¾ of a cup of warm water and oil and bring together to form a rough dough. Knead for about 5 minutes until the dough is soft and smooth. Transfer to a slightly warm,greased bowl and cover with a tea towel. Rest in a warm place for at least 30 minutes until the dough has doubled in size. Punch the dough down to remove any air,roll out into a long,thin oval shape and place on a large oven tray.
Brush the surface of the dough all over with olive oil,scatter the edges with a little sea salt,then press the onions into the surface.
Bake in the oven for 10 minutes or until dough is golden and cooked.
Heat remaining 1 tbsp oil in a frying pan over medium heat. Fry the sage leaves until crisp,about a minute. Scatter the hot flatbread with the cheese and sage leaves,drizzle a little more olive oil over the top and serve.
Adam's tip
Pizza dough freezes well and will keep for up to three months. Roll the dough into individual balls,freeze on a tray,and then store them in press-seal bags. Defrost the balls in the fridge or at room temperature as you need them.