Peel the prawns and remove the intestines. Wash the prawns and pat them dry. Wash basil leaves and pat dry. Divide the dumpling dough into 4 parts and press a hollow into it. Season prawns with salt and pepper and put 2 basil leaves in each hollow. Form into 4 round, smooth dumplings. Bring a pot of salted water to a boil at medium heat and let the dumplings simmer for about 20 minutes.
In the meantime, wash the lemon and grate it dry. Halve the lemon and squeeze one half. Put butter and lemon peel in a pot. Melt butter and add lemon juice. Season with salt, pepper and sugar. Lift the dumplings out of the pot, put them on plates and sprinkle with some butter