Name: Leftover cheese pies
Total time: 1 h 10 min
Yield: Makes 4
Ingredients: 2 large onions, finely chopped; 150g (about 1 medium) floury potato, cut into 1½cm cubes; 2 tbsp unsalted butter; 2 tbsp plain flour; 400ml whole milk; 400g left-over hard cheese (we used a mixture of cheddar, pecorino and gruyère), grated; 2 tsp English mustard; a pinch white pepper; 1 egg, beaten, to glaze; 2 x 320g ready-made puff pastry sheets; pickle or chutney, to serve

A white plate topped with a puff pastry tart, sliced open with melted cheese in the middle

2 large onions
finely chopped
150g (about 1 medium) floury potato
cut into 1½cm cubes
2 tbsp unsalted butter
2 tbsp plain flour
400ml whole milk
400g left-over hard cheese (we used a mixture of cheddar, pecorino and gruyère)
grated
2 tsp English mustard
a pinch white pepper
1 egg
beaten, to glaze
2 x 320g ready-made puff pastry sheets
pickle or chutney
to serve

Method

step 1
Put the onions and potato into a steamer basket and steam for 8-10 minutes or until tender.
step 2
Melt the butter in a pan over a low-medium heat, sprinkle in the flour and mix into a thick paste. Add the milk, a splash at a time, stirring continuously, until you have a lump-free white sauce. Cook gently for a few more minutes until thickened. Stir in the cheese and mustard, and season with a pinch of white pepper. Cook for a minute more until the cheese has melted, then remove from the heat and fold in the onions, potato and a little salt, depending on the saltiness of the cheeses. Transfer to a dish and cool to room temperature, then chill until you’re ready to bake.
step 3
Heat the oven to 200C/fan 180C/gas 6. Unravel the pastry sheets and cut each into two rectangles. Spoon the cheese sauce onto the middle of one side of each pastry rectangle, leaving a 1cm border.
step 4
Brush the exposed pastry border with the beaten egg, then fold over the other side and crimp the edge with a fork to seal. Transfer to a baking sheet lined with baking paper and brush with more egg. Cut a cross into the tops of the pies for steam holes. Bake for 40-45 minutes or until golden and puffed up. Cool for 10 minutes, then serve with pickle or chutney.