Peel the potatoes and cut them into 3 cm chunks. Put them in a 24 cm / 9-inch pot, cover with cold salted water, and bring to a boil. Cook for 15 to 18 minutes, until a fork slides in easily.

Drain well and mash the potatoes while they're still warm. Spread the mash on a plate and let it cool for about 10 minutes before mixing in the eggs, this stops the filling from turning gummy.

In a large bowl, mix the cooled mashed potato with the feta, eggs, dill, spring onions, milk, 2 tbsp olive oil, pepper, and nutmeg. Taste and add salt only if needed, feta is already salty.

Heat the oven to 180 C / 350 F. Brush a 23 x 33 cm / 9 x 13-inch baking dish with a little of the butter and oil mixture.

Combine the melted butter and remaining 3 tbsp olive oil in a small bowl. Lay one sheet of phyllo in the dish, letting the edges hang over the sides, and brush lightly with the butter mixture. Repeat with 5 more sheets, brushing each one.

Spread the potato and feta filling evenly over the phyllo base.

Layer the remaining 6 phyllo sheets on top, brushing each one with the butter mixture. Fold the overhanging edges over the top and tuck them in loosely.

Score the top into 8 pieces with a sharp knife, cutting through just the top layers of phyllo, this makes it easier to slice cleanly once baked.

Bake for 30 to 35 minutes, until the top is golden brown and crisp all over.

Let the pie cool in the dish for 10 minutes before cutting along the scored lines. Serve warm or at room temperature.