Wash the strawberries, dab dry and, except for 4 pieces for decoration, clean them. Put the strawberries and 1 tablespoon of sugar in a mixing cup and puree. Soak the gelatine in cold water. Mix buttermilk, remaining sugar and liqueur. Squeeze the gelatine, dissolve and stir into the buttermilk. Chill until the buttermilk begins to gel. Whip cream until stiff and fold in.
Divide into 4 portion moulds (approx. 125 ml each). Chill for about 5 hours. Spread the strawberry sauce on 4 plates. Dip the moulds briefly into hot water. Turn the flan over onto the sauce. Decorate with remaining strawberries and possibly with woodruff or lemon balm.