Wash lemon hot and dry. To decorate, peel some of the peel in thin strips with a zest ripper, finely grate the rest of the peel and squeeze the lemon. Mix quark, 2 tablespoons sugar, grated zest and 2 tablespoons lemon juice.
Whip cream until stiff and fold in.
Spread half of the lady fingers in a bowl. Mix the rest of the lemon juice, 4 tablespoons of water and 1 tablespoon of sugar and drizzle half over the sponge cakes. Spread 1/3 curd cream on top. Spread the remaining lady fingers on top and drizzle with the remaining lemon mixture.
Select the raspberries, wash them carefully if necessary and dab them dry. Put them on the lady fingers, except for a few for decoration. Cover with 1/3 cream. Spread half the lemon curd, then the rest of the cream and lemon curd on top.
Sprinkle with remaining raspberries and lemon strips. Leave in the refrigerator for at least 2 hours.