Lay out frozen pastry on a flat surface, separating each sheet with a sharp knife. Leave to defrost while preparing the filling. Preheat oven to 160deg fan-forced.
in the bowl of a food processor, process the spinach and the shallots,
Add the eggs and the cheeses and process further.
Add the flour to create a slightly thickened paste.
Cut each square of pastry into 4 smaller squares.
Place a dollop of filling into each pastry square and fold the corners in to create a smaller square and pinch the corners.
Brush with beaten egg and sprinkle with sesame seeds.
Bake in a preheated oven for about 30-40 minutes till golden brown.
Cool on a wire rake to prevent them going soggy.
Notes
These can be frozen after step 7, just lay them on a flat baking try and freeze over night. Then pack into freezer bags and bake as required.