Heat oven to 200C/180C fan/gas 6.
Fry onion, garlic, potatoes and
carrots in oil for 5 mins until softening.
Add peppers, paprika, herbs and
tomato purée, and cook for 5 mins.
Add stock, bring to the boil, then
simmer until stock is absorbed and
vegetables are tender. Add the tuna.
Roll a quarter of the pastry into
a 22cm circle. Roll remaining pastry
to line a 22cm loose-bottomed tin,
allowing the pastry to come over
the edges of the tin.
Fill with the tuna mix and top
with the pie lid. Brush the edges
with egg then fold over the sides
and press down with a fork to seal.
Make two holes in the top, brush
with egg and bake for 35-40 mins
until golden brown. Leave to cool
slightly, then serve.