Line a cake springform pan (22 cm ø) with cling film. Place the wafer rolls on the inside edge. Soak gelatine in cold water.
Beat egg yolks and 30 g sugar in a hot water bath with the whisks of a mixer until creamy. Bring milk to a boil and then pour slowly into egg mixture, stirring constantly. Melt the squeezed gelatine in four tablespoons of hot water and stir into the cream. Place in a large enough bowl with cold water and ice cubes and let cool.
Puree the washed strawberries (leaving a few for decoration), pass through a sieve and add a little Grand Marnier to taste. Whip 500 g of whipped cream (reserve a little for decoration) and the remaining sugar until stiff and fold into the cooled cream together with the strawberry puree. Pour the cream into the prepared mold. Place in the refrigerator for one night.
Whip remaining whipped cream until stiff, pour into a piping bag and pipe around the edge of the charlotte. Decorate with the remaining strawberries.