Tip the butter, flour and mustard
powder into a food processor with ½ tsp
salt and whizz until you can’t see any
lumps of butter. Add roughly 4-5 tbsp
cold water, a spoonful at a time, while
pulsing until the pastry comes together.
Tip out onto a clean surface, bring
together into a ball and chill while you
make the filling.
Melt the butter in a frying pan. Add the
onion and gently sweat for 10-15 mins
until really soft, but not very coloured.
Stir in the peas for 1 min, then turn off
the heat and stir in the ham, mint and
ricotta with plenty of seasoning.
Heat oven to 180C/160C fan/gas 4 and
divide the pastry into 4 equal pieces. Roll
each piece to a neat 16-17cm circle – cut
round a saucer or lid. Brush the edges
with a little of the beaten egg, spoon a
quarter of the filling into the middle, then
bring up opposite sides of the pastry
and seal. Crimp to make a pasty shape.
Carefully lift onto a baking sheet. Repeat
with the rest of the pastry, then brush
the finished pasties all over with egg.
Bake for 35-40 mins until golden and
crisp. Leave to cool slightly, then serve
either warm or cold.