Feuilleté au Jambon

Method

1. Preheat oven to 180°C fan-forced (200°C conventional).
2. In a medium saucepan, melt the butter over medium heat until melted, then add the flour. Increase the heat and stir constantly with a spatula until the mixture thickens. Gradually add the milk in a steady stream while whisking well, then leave on heat to thicken, whisking regularly until the mixture coats the back of a spoon and leaves a wide trail when swiped. Add nutmeg and salt and pepper to taste, then cover with cling wrap and set aside to cool completely.
3. Unroll the defrosted pastry sheet. Cut in half lengthways and place one half on a lined baking tray (put the other half in the fridge until needed). Top with a layer of béchamel, leaving a 3cm space at the edges. Add a double layer of ham on top of the béchamel, then top the ham with a layer of Gruyere cheese. Repeat with béchamel, ham and cheese, finishing with a final layer of béchamel.
4. Brush the pastry border with beaten egg, then place the chilled sheet from the fridge over the top of the pastry and filling. Press down around the border to secure the edges of the pastry together, then press around the filling from the top to remove any air pockets. Trim the edges into straight lines, then use a spoon to crimp the edges together around the border. Set aside in the fridge to chill for 15 minutes.
5. When ready to bake, brush the top with beaten egg and score a few horizontal lines from top to bottom over the centre of the filling.
6. Place in the oven and bake for 40-45 mins at 180°C fan-forced (200°C conventional) until pastry is puffed and dark golden. Serve immediately.