Preheat oven to 160'C. Grease a 30cm deep round cake pan with a touch of butter. Line the base and sides with baking paper.
Beat the butter and sugar together in a large bowl with a whisk until light and fluffy. Add the eggs one at a time, adding a spoonful of flour with every egg, beating until just combined between additions (the mixture may appear curdled at this stage).
Transfer mixture to a very large bowl and then fold in sifted flours, ground almonds and milk in three batches. Fold in the raspberries, then spread the mixture into cake mould.
Transfer to the oven for 1 hour and then reduce oven temperature to slow 150degrees and bake for a further 1 hour. Test by placing a cocktail stick in the centre, if it comes out clean your cake is ready. Stand for 20 minutes and then turn onto a wire rack to cool completely.
Toast the almonds in a dry pan for 3-4 mins until golden brown.
Beat the mascarpone, sour cream and icing sugar in a large bowl with an electric mixer until soft peaks form and then stir in the Grand Marnier.
Using a large serrated knife, carefully cut the cake into three layers. Place the base layer on a serving plate and cover with a layer of the mascarpone cream. Repeat twice more, finishing with a layer of cream.
Decorate top of cake with the flaked almonds and fresh raspberries.
«If using frozen rasberries, add them to the mixture when they are still frozen rather than defrosting them first. They will hold their shape and juice a lot better this way.»