In a small bowl, combine the butter, parsley, garlic powder and garlic salt. Cut dough into 1-in. pieces; dip into butter mixture. Layer in a greased 9×5-in. loaf pan. Cover and let rise until doubled, about 1 hour.
Bake at 350° for 30 minutes or until golden brown.
Place pork in a 30cm x 25cm metal baking tray. Rub all over with oil. Rub salts into scored skin. Roast for 20-25 minutes or until skin starts to blister.
Reduce oven to 180C or 160C fan-forced. Pour milk around pork (be careful of steam and to not pour any milk over the skin). Add garlic, sage and seeds to milk. Roast for 1 hour.
Increase oven to 260C or 240C fan-forced. Roast for 10 minutes or until skin is blistered and puffed all over. Remove from oven. Carefully lift pork out of braising liquid and transfer to a plate. Stand loosely covered with foil for 10 minutes before carving.
Prepare a grill for medium heat. Whisk lime juice, fish sauce, sugar, and 1 Tbsp. water in a small bowl until sugar is dissolved. Stir in garlic and cilantro stems; set nuoc cham aside.
Place pork on a rimmed baking sheet and season generously on both sides with salt and pepper, then drizzle with oil and turn pork to coat. Grill, turning often and moving around on grill to prevent flare-ups, until lightly charred all over and an instant-read thermometer inserted into the center registers 140° for medium), 12–15 minutes. Transfer meat to a cutting board and let rest 10 minutes before slicing.
Spoon some of nuoc cham over pork and top with cilantro leaves. Serve remaining sauce alongside.