Even though it remains a legend that marzipan was invented in the Hanseatic city of Lübeck, the production of fine marzipan does have a long tradition there.
1. Grind the almonds in the food processor to a very fine powder. Add the confectioner's sugar and the rose water and keep grinding until a thick, smooth paste forms. Add drops of water to get the desired consistency but do not overdo it, otherwise your marzipan will become difficult to shape. Scrape down the sides of the food processor bowl frequently to ensure that all the paste is smooth.
2. Roll the paste about ½ inch thick with a heavy rolling pin. If the marzipan is too sticky and moist, dust the work surface with confectioner's sugar. Cut the marzipan into 1-inch squares and place them on a baking sheet. Let the marzipan dry for 8 hours in a cool oven or other cool, dry place. Store it in a tightly covered tin, inserting aluminum foil between the individual layers. Homemade marzipan keeps for 1 to 2 weeks, after that, it becomes a bit dry but still tastes good.
Source: Nadia Hassani: “Spoonfuls of Germany” (Hippocrene Books, 2004)