Preheat the oven to 200°C/400°F/Gas Mark 6.

Cheese sauce

First make the sauce. Put a saucepan over a medium-low heat, add the butter plus a pinch of salt and pepper and melt slowly. Add the flour, whisk until well combined, then cook for 2 minutes.

Take the pan off the heat and slowly add a quarter of the milk, whisking until smooth. Return the pan to the heat, add another quarter of the milk and whisk again. Increase the heat to medium high, add the remaining milk and heat for 1–2 minutes, until beginning to thicken. Add the Pwll Mawr cheese, stir until thick and creamy, then mix in the Worcestershire sauce. Set aside.

Dragon's pie

Place the leeks in a saucepan with just enough water to cover them. Bring to the boil over a medium-high heat, then simmer for about 5 minutes, until starting to soften. Drain, then place on a clean tea towel to cool and dry.

Put the potatoes in a saucepan of salted water, bring to the boil, then simmer for 15–20 minutes, until just soft enough to mash. Drain, add the butter and mash the potatoes until light and fluffy.

Season to taste.

Wrap each cooled leek in a strip of ham and place in a large ovenproof dish (about 20 x 15 x 15cm/8 x 6 x 6in). Cover them with the cheese sauce, then smooth the mashed potato over the top.

Sprinkle with the Dragon’s Breath Cheddar and place in the oven for 20–25 minutes, until the pie is thoroughly hot in the middle and golden brown on top.

Serve

Serve with crusty bread.