In a bowl mix together the flour and salt. Add the yoghurt and olive oil and knead until you have a smooth and elastic dough. Add a bit more flour if the dough is too wet or a bit more yoghurt if the dough is too dry. Cover and set aside for 20 mins to rest.
You can start making the harissa mushrooms while the flatbread dough is resting.
Heat some olive in a large frying pan. Add the finely chopped onion and the crushed garlic. Fry gently until soft.
Add the diced pepper and the sliced mushrooms. Fry on medium to high heat until the mushrooms start to soften.
Add the chopped tomatoes, drained chickpeas, cumin, smoked paprika and rose harissa. Simmer on medium heat until the mushrooms and pepper are cooked and the sauce has thickened. Reduce the heat to low if you feel the vegetables are becoming too dry.
While the mushrooms are cooking, you can start cooking the flatbreads.
Cut the dough into 4 even balls. Add flour to your working surface and roll out each dough ball to a 20cm / 8 inches circle.
Heat a non-stick pan on high. When the pan is very hot, place the first flatbread in it. Do not use any oil or grease, simply cook the flatbread 2 mins or so on each side until it starts to char. When done, keep it covered in a warm oven while you cook the rest of the flatbreads.
Just before serving, add a handful of chopped coriander leaves to the harissa mushrooms. Season to taste with lemon juice and salt.
Place some harissa mushrooms on top of each flatbread. Top with some yoghurt and fresh coriander.