Chocolate cream

Melt chocolate in the top of a double boiler over simmering water, or in the microwave oven (2 to 3 minutes at 80 percent power). Stir until smooth, then beat in butter.
Add egg yolks one at a time, beating well after each addition. Stir in brandy, if using.
In a clean bowl, whisk egg whites lightly until frothy, preferably using an electric hand beater. Add cream of tartar and whisk briskly until soft peaks form.
Stir a third of egg whites into chocolate mixture. Then fold in remaining egg whites, using a slotted spoon. Pour into a 1 litre (4 c) mould and smooth top. Cover and freeze until ready to serve.
SUGARED ROSE PETALS: Whisk egg white lightly with a fork until mixed but not frothy.
Paint rose petals with egg white, placing each petal on a sheet of paper thickly sprinkled with castor sugar as you finish it.
Sprinkle more castor sugar over the top. Leave in an airy place to dry. To serve, scoop spoonfuls of chocolate cream on to plates and decorate with sugared rose petals.