Spinach and Feta Custard Pie

Place the egg, egg yolk, sugar, and cornflour (corn starch) into a mixing bowl and whisk together until frothy. Set aside.

Place the milk into a medium saucepan over a medium heat. Add the black pepper, thyme sprigs, and the pinch of salt and bring to a boil.

Once the milk is boiling, remove the thyme from the pan using a fork, then pour the hot milk into the egg mixture, whisking continuously for 1–2 minutes to form a custard.

Pour the custard back into the pan and place over a low heat. Little by little, add the semolina, whisking to combine between each addition. Keep whisking until the mixture is thick enough to come away from the bottom of the pan. Then, continue to stir for 1–2 minutes, until the custard is thick and has the consistency of mashed potato.

Remove the pan from the heat and add the butter, stirring until it is completely melted and combined. Set aside and allow the custard to cool.

Meanwhile, heat the oil in a large pan over a high heat. When hot, add the onions and season with salt and pepper. Fry for 8–10 minutes, until golden brown, then add the nigella 1–2 minutes. Tip the contents of the pan onto a plate and set aside.

Put the pan back on the heat. Add the spinach and about 100ml (3½fl oz) of water, stirring occasionally to make sure the spinach doesn’t stick. Cook for about 5–10 minutes, until the leaves are fully wilted and the water has evaporated.

Stir in half the cooked onion mixture and set aside for 10 minutes to cool. (Alternatively, you can make the filling the day before, if you like.)

Add the remaining onion mixture to the custard. Add the feta and stir to combine and season with salt and pepper. Set aside again.

Once the filling has cooled for 10 minutes, lay out 1 sheet of filo pastry, with the longest edge closest to you. Brush the whole sheet with a thin layer of melted butter, then add another sheet of filo and brush again with butter. Add the final sheet of pastry. Spoon the custard into the middle, smoothing it out into a square, leaving at least a 3cm (1¼in) border around the edges. Add the spinach mixture on top, spreading it out evenly. Fold the pastry edge closest to you up and over the filling and fold down the edge farthest from you. Then, fold in the two sides, so that the filling is fully encased.

Lightly butter a baking tray or line a baking tray with greaseproof paper. Carefully flip the tart over so that the folded sides are underneath and transfer it to the baking tray. Brush the top of the pie with melted butter and sprinkle over the sesame seeds and extra nigella seeds. Bake for 20–25 minutes, until golden.