1. Preheat the oven to 200C fan-forced or 220C conventional. Line two baking trays with baking paper.

2. Discard about half of the stem from the silverbeet and finely shred the remaining stem and the leaves.

3. Add half the oil to a large frying pan, or wide, shallow saucepan, over medium heat and fry the onion and garlic until translucent. Add the silverbeet and cook, stirring frequently, until wilted and tender, about 10 minutes. Tip into a large bowl, draining off any excess liquid if necessary.

4. Add the remaining oil to the pan and crumble in the sausage meat. Fry until lightly golden, sprinkling over the spices towards the end. Tip into the bowl with the silverbeet and set aside to cool for five to 10 minutes.

5. Add two eggs, the cheese, herbs, sesame seeds and citric acid (if using) to the bowl with the silverbeet, season with salt and pepper and combine well.

6. Cut each sheet of pastry into four. Beat the remaining egg and brush the edges of one of the pastry squares. Dollop about one heaped tablespoon of the mix in the middle and bring each point of the square up to meet the point diagonally opposite it. Seal by pinching the edges together, and then brush the top with egg. Sprinkle over the nigella seeds and repeat for the remaining filling. Bake for about 25 minutes on the prepared trays until lightly golden. Serve warm or cold.

TIPS
1. Try this with chicken mince, rather than sausage meat.
2. The pies can be frozen once assembled.
3. You could omit the meat altogether for a vegetarian version and add ricotta instead

*The citric acid is definitely optional in this recipe, but it does add a lift and zing that's hard to replicate. It's a bit of a secret ingredient in Middle Eastern pastries, and it works particularly well in recipes like this, making the greens lively and bright, where they can otherwise be a bit flat.