If you have some chicken left over from Sunday lunch, chop up 125g and stir it into the risotto along with the peas.
Melt the butter in a saucepan, then add
the onion and garlic. Cook for 4-5 mins
until softened, then stir in the rice.
Pour in a ladleful of stock and simmer
until all the liquid has been absorbed,
stirring occasionally. Continue adding
the stock in this way, until it has all been
used up and the rice is tender. Stir in the
peas and tarragon, then heat through for
2 mins. Check seasoning, then stir in
the Parmesan and serve straight away.