One approximately 4 lb pork loin roast dry-brined with kosher salt and coated with a paste of Dijon mustard, olive oil, garlic, fresh rosemary, black pepper, onion powder, smoked paprika, and brown sugar or honey.
Prepare & package
Combine the salt, Dijon mustard, olive oil, garlic, rosemary, black pepper, onion powder, smoked paprika, brown sugar or honey, and any optional MSG or lemon zest into a paste. Coat the pork completely. Vacuum-seal and refrigerate overnight for next-day cooking, or freeze for later use. Do not add lemon juice or vinegar.
Store & thaw
Keep vacuum-sealed and frozen. Thaw completely on a tray in the refrigerator before cooking. The cooking time below is for a fully thawed, refrigerated roast; do not thaw at room temperature.
Cook or reheat
Sous vide the fully thawed, refrigerated roast at 137°F for 5–6 hours. It may remain in the bath for up to 6–7 hours if necessary. For pork with a slightly firmer, more conventionally cooked texture, use 140°F.
Finish & serve
Remove the roast from the bag and discard the bag liquid. Scrape away loose garlic, rosemary, and paste that could burn, then pat the pork extremely dry. Heat a large cast-iron skillet over medium-high heat until very hot and add a thin film of high-smoke-point neutral oil. Sear the roast for 45–60 seconds on each broad side and 20–30 seconds on the narrower edges, turning with tongs, until deeply browned. Work quickly to avoid overcooking the interior. Rest for 3–5 minutes, then slice across the grain.