To make the brine: Add the salt, sugar, onion, garlic, thyme, rosemary, fennel seeds, coriander seeds and 1 1/2 quarts of cold water to a large container and stir to combine. Submerge the pork in the brine and refrigerate for 2 hours.
Preheat the oven to 400 degrees F.
Remove the pork from the brine and pat dry. Season with salt, pepper and the fennel pollen. Wrap in the prosciutto and caul fat.
Heat a large saute pan on medium-high heat and add enough oil to coat the bottom of the pan. When the oil is close to its smoking point, sear the pork on all sides until golden brown. Transfer the pork to a sheet pan and reserve the saute pan and drippings. Roast until medium doneness and the internal temperature reaches 150 degrees F, about 5 minutes. Allow to rest.
Discard the excess fat in the saute pan used to sear the pork. Add the vinegar and reduce until nearly dry. Add 1 cup of the chicken stock and reduce to half. Add the remaining cup of chicken stock and reduce until about 1/3 cup remains. Remove from the heat and swirl in the butter. Season to taste.
Slice the pork on the bias and serve over the Flageolet Ragout and Frizzled Brussels Sprouts Leaves. Drizzle with some of the pan sauce.
Combine the flageolets and chicken stock in a medium saucepan. Season with salt and bring to a boil. Reduce to a simmer and cook until tender, about 30 minutes. Set aside.
Add a drizzle of oil and the sausage to a large pan over medium-high heat. Brown the meat, breaking it up as it cooks. Remove from the pan and set aside. To the same pan add the fennel, onion, garlic and red pepper flakes. Deglaze with the wine and cook until the fennel and onions begin to caramelize. Return the cooked sausage to the pan and add the flageolets and ramp seeds. Heat through, adding more chicken stock if necessary to keep everything moist. Season to taste. Drizzle with extra-virgin olive oil to finish.
Frizzled Brussels Sprout Leaves:
Heat a large saute pan over medium heat and add enough oil to coat the bottom of the pan. Add the garlic and cook until aromatic and slightly golden. Add the Brussels sprouts, season with salt and saute until slightly charred but not too soft. Remove from the heat, add the anise hyssop and toss to combine.