Preheat the oven to 180C (fan 160C).

Chop the potatoes into 3-4 cm chunks and place into a saucepan with a big pinch of salt. Cover with cold water and bring to a boil (tip: use cold water for old potatoes and boiling water for new potatoes). Simmer for about 15 minutes until tender when pierced with a knife. Drain well in a colander.

Heat 1 tablespoon of the olive oil in a large frying pan. Add the leek or onion with a pinch of salt and sauté until softened, about 5-6 minutes. Add the greens along with 1 tablespoon of water, cover with a lid and steam for 5 minutes. Then remove the lid and sauté until excess moisture has evaporated - turn up the heat if needed. Remove from the heat.

Tip drained potatoes into a large bowl and use a fork to roughly mash. Add the dill and cheese, and season well with cracked pepper. Tip in the greens mixture and combine. Taste and adjust seasoning as needed.

In a small saucepan, melt the butter with the remaining 2 tablespoons of olive oil. Use this to grease a 25cm round baking dish (or similar).

Unroll the filo and lay two sheets stacked together on the bench with the longest side closest to you. Use a pastry brush to generously brush with the melted butter. Spread about 3 heaped tablespoons of the potato mixture along the long edge of the filo. Roll up the pastry into a log, brushing along the length of the exposed pastry as you go. Coil into a spiral (not too tight) and place into the prepared dish. Repeat with the remaining filling mixture and filo sheets.

Scatter with sesame seeds and bake for 25-30 minutes until golden.

Serve with a spring salad, and chutney or seasoned yoghurt on the side.