Horseradish.

This one is just two years old and it has started having babies.  Dig up older tubers.  Finely grate the root and mix it with vinegar immediately.  You can peel it if you like, but it is not necessary.  You can add some cream to the mixture as well.  Experiment with different vinegars for different flavors,  You can eat the tops too....just nibble one and see what you think.