Mix the flour and salt in a bowl and add the yeast. Combine the water, yoghurt and oil, pour in, knead to form a soft, smooth dough. Cover and leave to rise at room temperature for approx. 1 hr.
Heat the oil in a frying pan, brown the mince. Add the onions, pepper, tomatoes and tomato puree, sauté for approx. 3 mins. Add the thyme, season, simmer for approx. 2 mins.
To shape & bake
Cut the dough into 4 equal pieces. On a lightly floured surface, roll the dough into ovals. Spread the filling in the middle, fold the edges inwards and press down gently.
Bake for approx. 25 mins. in the centre of an oven preheated to 200°C.
Garnish with the reserved onion greens prior to serving.