Heat oven to 220C/200C fan/
gas 7. Lay the pastry out on a
baking sheet. Pinch up the edges
to form a border, pressing firmly
into the corners. Prick the centre
all over with a fork and pop in
the oven for 10-15 mins.
Meanwhile, mix the tuna and
sweetcorn in a bowl and season.
Remove the pastry from the
oven, pressing the centre down
with the back of a fork, as it
will have puffed up a bit. Spread
the crème fraîche across centre,
spoon the tuna mix on top, then
sprinkle over the cheese. Bake
for 10-15 mins more, until golden,
puffed up and cooked though.
Sprinkle with chives and cut