Gravenstein Apple Mustard
Soak the mustard seeds: Place the mustard seeds and powder in a medium glass or ceramic bowl along with the balsamic and hard cider overnight.
Place the mixture in a food processor along with the salt and process for 1 to 2 minutes until the seeds are coarsely ground.
Add the grated apple and pulse a few times to incorporate. This makes about 1 2/3 cups mustard.
The mustard will be very pungent at first. Cover and refrigerate for a few days (or to taste) before using.