Fill a large pot with water and add the juice of 2 lemons, 4 flat-leaf parsley springs and 2 dried bay leaves. Bring to a boil over high heat and then let simmer for 15 minutes.
Meanwhile make the pickling liquid. In a large bowl, combine the juice of the two remaining lemons, olive oil, vegetable oil, capers, salt, apple cider vinegar, garlic cloves, bay leaves, red pepper flakes, celery seeds, mustard seeds and freshly cracked black pepper, if desired.
Whisk until thoroughly combined. Set aside.
Add the shrimp to the simmering poaching liquid from step one. Make sure the water is not boiling or else you could overcook your shrimp. Once your shrimp begins to curl and turn bright pink, remove from heat.
Drain the shrimp but do not rinse them.
Let shrimp cool then add to the pickling liquid. Pickle at least 4 hours, but up to a few days.
Combine the onion, red wine vinegar, water and honey in a large mixing bowl. Let sit for 30 minutes.
Add the butter beans, pickled shrimp, celery, celery leaves, cucumber, parsley, mint, extra-virgin olive oil, whole grain mustard, salt, black pepper, crushed red pepper flakes and freshly cracked black pepper; stir to incorporate. Add rice, if you'd like.
Cover and refrigerate for 30 minutes, or up to overnight. Add bacon right before serving, if desired.
