An nifty, classy-looking creamy, strawberry mousse flavoured with orange zest and Cointreau. Looks as if it would probably have taken ages to make. But it won't have done. Just don't let on. For a non-alcoholic version, omit the Cointreau. The chilling time has not been included in the time taken between preparing the mousse and serving it. This mousse can also be made with other berries or with other fruits.