Drain the jackfruit and place into a glass dish (so it won't stain from the beet juice) and add the pickling spices and all of the juice from a can of beets. Reserve the beets for another meal. Marinate for several hours (best if overnight).
TO MAKE THE MUSTARD SAUCE:
Combine everything (except the almond milk) with a whisk in a small saucepan and over medium heat, stir constantly until it begins to thicken. Add almond milk to thin.
TO FINISH THE RECIPE:
Cook the cabbage wedges in boiling water until tender.
Add the jackfruit, the liquid, the mushroom broth, salt, pepper, onion and carrots to a slow cooker on high heat. Depending on your slow cooker, it can take anywhere from 2-4 hours.
Serve with a side of the mustard sauce, extra vinegar for the cabbage (if desired) and a pinch of salt and pepper. Garnish with fresh parsley.