Ingredients

• 75g/2½oz unsalted butter
• room temperature
• 75g/2½oz lard
• room temperature
• 200g/7oz plain flour
• ½ tsp salt
• ½ tbsp white wine vinegar
• about 150ml/5fl oz chilled water
• 30g/1oz butter
• 280g/10oz onions
• peeled
• thinly sliced
• 1 tsp salt
• 2 tbsp caster sugar
• 930g/2lb 1oz potatoes
• preferably Marabel variety
• peeled
• thinly sliced
• 140g/5oz crème fraîche
• 4 tbsp double cream
• 100g/3½oz mature cheddar
• grated
• 100g/3½oz Stilton
• crumbled
• 100g/3½oz Gruyère
• grated
• freshly ground black pepper
• 1 tsp grated nutmeg
• 1 free-range egg
• beaten

Directions

• To make the pastry
• place the butter and lard into a bowl and mash with a fork until soft and creamy. Divide the mixture into four equal portions.
• Place the flour into a bowl and add the salt. Take one portion of the butter/lard mixture and rub into the flour until the mixture resembles breadcrumbs. Add the white wine vinegar and mix it in using a blunt knife. Add just enough cold water to form a dough then turn it out onto a floured work surface.
• Shape the dough into a rectangle and roll it out to a thickness of about 1cm/½in. Gently lift the pastry with your fingers and allow it to shrink back a little.
• Cut another portion of the butter/lard mixture into small pieces using a palette knife and dot it over the pastry
• being careful not to get it too close to the edges. Fold the pastry into thirds
• rubbing off any excess flour as you do so
• cover in cling film and place in the fridge for five minutes.
• Take the pastry from the fridge. Repeat steps 3 and 4 using the remaining butter/lard mixture. If any fat shows through the pastry
• scatter over a little more flour.
• Remove the pastry from the fridge
• roll once more into a rectangle about 1cm/½in thick
• fold into thirds and return to the fridge for 30 minutes.
• Meanwhile
• make the filling. Heat the butter in a wide pan and add the onions
• salt and sugar. Fry over a low heat
• stirring occasionally
• for 5-6 minutes
• or until the onions are lightly caramelised. Remove the pan from the heat and set aside.
• Cook the potatoes in a large pan of boiling
• salted water for eight minutes
• drain well then set aside.
• Preheat the oven to 220C/425F/Gas 7
• with a rack is just above the middle of the oven and a baking tray underneath to catch any filling that might escape during cooking.
• Mix the crème fraîche
• cream and cheddar in a small bowl. Mix together the Stilton and Gruyère in a separate bowl.
• Layer one quarter of the potatoes
• a third of the onions and a third of the Stilton/Gruyère mixture in the bottom of a large pie dish. Sprinkle with a little freshly ground black pepper and grated nutmeg.
• Repeat step 11
• working from the outside of the pie dish into the middle to achieve a domed effect
• seasoning as you go
• then pour over half the cream/cheddar mixture. Repeat this step then cover the filling with the remaining potato
• ensuring none of the cream mixture is visible.
• Take the pastry from the fridge and place on a floured work surface. Roll out in one direction only
• turn 45 degrees and roll again until you have a piece of pastry that is a little larger than the pie dish. Lift the pastry with your fingers to allow it to shrink back a little.
• Cut thin strips from each edge of the pastry and use a little egg wash to stick each one to the rim of the pie dish. Brush each strip with beaten egg and carefully place the pastry over the filling
• pressing it down on the pastry strips to make a good seal.
• Take a fork and press down gently around the edges of the pie. Use any off-cuts of pastry to decorate the pie then brush the top with the remaining egg wash. Cut a small cross in the top of the pie to let the steam escape.
• Transfer the pie to the oven and bake for 30 minutes then reduce the oven to 180C/350F/Gas 4 and bake the pie for one hour or until golden-brown.