"Never be afraid to add plenty of butter," my mother says. She doesn't use scales but always gets it just right. Free-form tarts, of course, can be filled with any selection of delicious flavour. For mine I have used spinach and ricotta with a hint of blue cheese. These are always great to serve for lunch when my mum and sisters come for lunch.
To make the pastry, place the flour, butter and salt into the bowl of a food processor. Pulse until it resembles fine breadcrumbs. Add the egg yolk and water and mix until a firm dough. Wrap and refrigerate for 30 minutes.
Preheat oven to 180C.
To make the filling, in a large bowl combine the spinach, onions, ricotta, eggs, parmesan, salt and plenty of ground pepper.
Roll the pastry on a lightly floured bench into a 30cm circle. Place onto an oven tray.
Spoon the filling into the centre of the pastry leaving a 2cm border. Fold the edges in onto the filling, around the entire circle. Crumble the blue cheese over the filling. Brush the pastry with the egg yolk.