Making 'Wild Linden Chocolate"
The linden (or European Lime) tree is a native to Europe and North America. It's a very versatile tree and it has a whole range of culinary uses (here you can learn about the linden tree and its edible uses). One of the most remarkable is a chocolate substitute you can make from the fruit.
The linden tree (any of the species Tilia x europaea, Tilia cordata, Tilia platyphyllos, Tilia americana etc) has fruit that contain nut-like seeds. These have a range of essential oils and many of these have properties that make them taste like chocolate. All children living near linden trees will know of this 'tree chocolate' and this was a well-known property of linden fruit.
As the fruit matures and hardens the chocolate flavour becomes lost. As a result, it is possible to dry and grind linden fruit as a coffee substitute that tastes a little like coffee with a little hot chocolate added it's nowhere near as strong in chocolate taste as the immature fruit.
It wasn't until the 18th century that people began to experiment with linden fruit to try and make something more palatable from it. As a result, the French chemist, Missa discovered that by grinding the immature fruit of linden trees with dried linden flowers he could obtain a product that had an aroma similar to chocolate.
This seemed like a very exciting discovery and the process was tentatively commercialized in Prussia (what is now Germany, the heartland of where the European linden or lime tree grows). However it was soon discovered that the product did not keep well and the large-scale production of 'linden chocolate' was quickly dismissed. Indeed, the recipes and secrets of how the chocolate was made was almost completely lost in the mists of time and only recently have Missa's processes come to light.
Nothing will induce linden chocolate to develop a long shelf life, but it's possible today to make linden chocolate in small batches and freeze for later use (it will still denature and lose its chocolatey flavour quite quickly though). If you are going to make it then I suggest you dry linden flowers and freeze whole immature linden fruit for later use. You can then make the product on the day you want to use it and you can capture it's amazing aroma.
Here is the process you will need to make linden chocolate:
500g immature linden tree fruit (with stalks removed)
40g dried linden flowers
a little grape seed oil
Grind the linden flowers to a powder and set aside. Meanwhile pound the linden tree fruit to a paste in a pestle and mortar (or a food processor). Mix the linden tree fruit with the dried linden flowers and add just enough grape seed oil to make a manageable paste. This is best used the same day but can be kept for a few days by freezing in the refrigerator.
If you want a recipe using this product then the Celtnet Recipes Archive has a recipe for Linden Chocolate Mississippi Mud Pie. I've also found a blog with a recipe for a Linden Leaf Porridge.
There are also tens more recipes including many other parts of the linden tree in the Celtnet Wild Foods Recipes pages (you also get hundreds of recipes for other wild foods here!