Fold the mushrooms and a cup of the stock mixture into the barley.

Then slowly beat the cream mixture into the stock mixture.

Pour the stock mixture through the lined sieve to strain.

Whisk in the reduced stock mixture and set aside.

Add butter and reduced stock mixture, return to heat, cook and toss a few minutes more.

Remove the stock mixture from the heat and carefully whisk a ladleful into the mayonnaise.

Add half of the basil to the boiling cream and stock mixture.

Bring the reduced stock mixture to a boil.

Put this stock mixture in a saucepan and bring to a bare simmer.

Pour enough stock mixture over the chicken and vegetables just to cover.