Traditionally the heart-shaped moulds were made of wicker; now china ones are used. If you decide to use cream cheese, make sure it is unsalted. Press the cheese through a fine sieve into a mixing bowl and stir in first the double cream then the sugar. Beat until light and fluffy. In a small bowl, beat the egg whites just until stiff. Fold them carefully into the cheese mixture. Line six moulds with fine damp muslin or cheesecloth. Spoon the cheese into the prepared moulds, tapping the sides gently to allow the mixture to settle. Fold the ends of the cloth over the moulds, place them on a cake rack and refrigerate overnight. To make coulis, liquidize the raspberries and sugar to a smooth puree. Add lemon juice to taste. Pass through a sieve into a small bowl. To serve, spoon a little of the raspberry coulis on to each serving plate. Discard any draining liquid and unmould the heart-shaped desserts on top of the sauce. Drizzle with cream and surround with the raspberries.