1. Sort the bilberries, tip them into a bowl of water and skim off any leaves or stalks that rise to the surface.
2. Transfer the bilberries to a sieve, rinse under cold water, then tip them into the water in a saucepan with the sugar and lemon juice.
Cover the pan and cook over a low heat for 15 minutes, until the bilberries are soft.
3. Keep 12-16 cooked bilberries in reserve for the garnish. Tip the remaining bilberries with the juice into a sieve over a bowl. Press the bilberries through the sieve and stir with the juice.
4. Dissolve the gelatine in a little hot water in a bowl over a saucepan of hot water, stir it into the warm bilberries and leave until cold.
5. Whip the cream until stiff, keep 4 tablespoons in reserve and fold the rest into the cold bilberries.
6. Fill 4 individual glasses with the bilberry cream and chill in the refrigerator until set.
7. Before serving, garnish each bilberry cream with a piped whirl of cream and a few bilberries.