Preheat oven to 400 degrees F
Butter a 10-inch tart pan and set aside.
Toast the walnut pieces on a cookie sheet in the oven for 15 minutes, remove and chop roughly. Toast the walnut halves the same way, but leave whole and set aside. Place the egg yolks in a mixing bowl and beat to a ribbon with the powdered sugar. Add the flour and the toasted chopped walnut pieces and stir through with a spoon. Whip the whites to firm peaks and carefully fold into the walnut and sugar mixture. Pour the batter into the prepared tart pan and place in oven to cook through, about 30 minutes. Remove and allow to cool 30 minutes.
Cut the cake carefully across the equator with a bread knife to form 2 thinner disks and place the bottom one on a cake presenter. Using a pastry brush paint the bottom disk's top face up with the maraschino liqueur. Whip the cream to firm peaks and place half of the cream on the first disk. Paint the cut side of the remaining disk with the maraschino and place face down on top of the cream and other disk. Cover the top with the remaining whipped cream and sprinkle with the toasted walnut halves. Allow to sit for at least 20 minutes but not more than 3 hours. Cut into slices and dust each piece with powdered sugar.
