For the Posset:
Bring the cream and sugar to the boil in a thick-bottomed pan.
Add the juice and zest of the lemons. Infuse for 5 minutes.
Pass through a fine sieve into a jug, and then divide between the glasses.
Refrigerate until set.
Top with raspberries and a dusting of icing sugar.
For the Biscuits:
Cream the butter and both sugars. The beat in the eggs one at a time.
Sift the flour, bicarbonate of soda and salt and fold int the batter.
Add the stem ginger and mix well.
Divide into marble-sized pieces and press flat onto a lined baking tray.
Bake at 175°C for 10-15 minutes.
Cool and dust with icing sugar before serving with the posset.