Whisk together the buttermilk, lemon zest, salt, pepper and thyme in a large bowl.
Place the pork chops in a heavy duty zip top bag and pour the buttermilk mixture over top. Press out the air and seal the bag.
Place the bag in a large bowl and store in the refrigerator for 1 hour or up to 24 hours.
Preheat oven to 400 degrees.
In a wide, shallow dish, whisk together the bread crumbs, cheese and parsley. Season with salt and pepper.
Put the butter in the center of a baking sheet and transfer the baking sheet to the oven to melt the butter, approximately 5 minutes.
While the butter melts, remove the pork from the brine. Discard the brine.
Dredge a pork chop in the bread crumbs by dipping each side and pressing down so the breading adheres to the surface of the pork. Transfer to a platter and repeat with the remaining pork chops.
Add the potatoes and onions to a large bowl. Pour the olive oil over the potatoes and toss to coat. Season with salt and pepper.
Remove the baking sheet from the oven and immediately arrange the pork on the baking sheet. Scatter the potatoes and onions around the pork chops. Transfer the baking sheet back to the oven and bake the pork chops for 25 minutes or until an instant read thermometer reads 145 degrees. (If your pork chops do not look crispy and golden brown, turn on the broiler for 1-2 minutes to crisp up the crust.)
Cover the pork chops with foil and rest for 10 minutes.
Serve the pork chops immediately with the potatoes and onions.