Pre heat oven to 180°C. Grease and line 2 baking trays

In a medium bowl, sift flour and arrowroot. Add sugar and use fingertips to rub butter in until it resembles fine breadcrumbs

Add yolks and 1 tablespoon water, use a butter knife to mix into a soft dough

Use hands to bring together in the bowl. Turn out onto a lightly floured bench, knead gently to smooth

With a lightly floured rolling pin, roll to 5mm thick. Use a 10cm round cutter to cut into 8 discs

Place discs onto prepared trays and bake 12 -15 minutes or until golden. Cool

Cut plums into wedges or halves, remove stone

In a stand mixer, whip the cream to soft peaks, add the mascarpone and remaining ingredients, gently mix until combined. Place one short cake on a plate, top with plums and mascarpone cream. Dust with icing sugar