Make mascarpone filling: Combine cheese and sifted sugar in a large bowl. Beat egg whites in a small bowl with an electric mixer until soft peaks form. Fold egg whites into cheese mixture, in two batches.
Place base of panettone onto serving plate. Sprinkle with 1 tablespoon of liqueur; spread with one-third of filling and scatter with one-third of the raspberries. Top with another slice of panettone. Repeat to make another two layers, finishing with mascarpone filling. Refrigerate, loosely covered.
Remove panettone from refrigerator 30 minutes before serving. Top with remaining raspberries; dust with sifted icing sugar.
Store the reserved panettone in plastic wrap and toast for breakfast. We used grand marnier in this recipe but you could use any citrus-flavoured liqueur you like. This dessert is best made the day before or up to 5 hours before serving to allow the flavours to develop. You can make it with all kinds of seasonal fruit – mixed berries, sliced peaches, plums, nectarines or mango would all work well.Note