Melt the chocolate and butter together over a LOW heat.

Add the egg yolks one at a time and whisk till smooth.

Add cream and whisk in well.

In a separate bowl beat the egg whites, salt and essence with an electric beater adding sugar in thirds as you go.

When the whites form stiff peaks fold it gently, but thoroughly, into the chocolate mixture.

Chill.

Serve in a whisky glass with whipped cream or berries or both.