For the dough, combine the yeast, flour, sugar, 1 tsp salt, the olive oil and 250ml warm water. Do this in a stand mixer with a dough hook attachment for 8-10 mins, or lightly dust a surface with flour and knead until smooth and elastic. Lightly oil a clean bowl and tip in the dough. Cover and leave to rise for 1-2 hrs until doubled in size. (This may take slightly longer depending on how warm your kitchen is.)

Meanwhile, finely slice one bunch of spring onions, then cut the other bunch in half to roughly separate the white parts from the green. Heat 3 tbsp oil in a small frying pan over a medium heat and cook the finely sliced spring onions, the garlic, chilli and nigella seeds until the garlic is fragrant and sizzling, about 2-3 mins. Strain the mixture in a fine sieve set over a bowl, reserving the oil. Tip the yogurt and 150g feta into a food processor and blitz until smooth, or do this using a hand blender. Stir in half the spring onion and garlic mixture, along with some seasoning, and chill until needed. Will keep chilled for a day.

Lightly dust a clean work surface with flour and tip out the risen dough. Split into four pieces and shape into balls. Cover and leave to rest for 5 mins. Roll each one out as thinly as possible, then lift and stretch the dough using your hands. Heat a heavy-based or cast-iron frying pan over a medium-high heat. Brush each side of the flatbreads with the reserved garlic oil, then cook for 2-3 mins each side until puffed up and charred. Remove and wrap in a clean tea towel to keep warm and soft, then repeat with the remaining flatbreads. Toss the halved spring onions with the remaining 1/2 tbsp olive oil, and set the pan over a high heat. Cook the spring onions for 3 mins undisturbed, then shake the pan to shuffle them, doing this until charred all over. Set aside.

To assemble, brush a little more garlic oil over the flatbreads, then top with the yogurt mixture and charred spring onions. Scatter over the remaining spring onion mixture, and the feta, then drizzle over a little more of the garlic oil, if you like.