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beef and porkeasy

Garlic-Herb Crusted Pork Loin Roast

Costco's boneless pork loin roast gets a garlicky herb crust and a simple sear-then-roast treatment that delivers juicy results every time.

Prep Time
15 min
Cook Time
1 hr
Servings
8
Cost / Serving
$2.00

Quick Answer

Coat Costco's boneless pork loin in a garlic-herb butter, sear all sides in a hot pan, then roast at 375°F until 145°F internal (about 35 minutes). Rest 10 minutes before slicing. Total 75 minutes; serves 8.

Costco sells boneless pork loin roasts in the 3–4 lb range, and they are one of the best values for feeding a crowd — mild, lean, and forgiving enough for a weeknight roast. A quick sear in a hot oven-safe pan builds a crust before finishing in a 375°F oven to 145°F internal temperature. A garlic-herb paste applied before searing drives flavor into every slice. This recipe feeds 8 and the leftovers are excellent for sandwiches, grain bowls, and fried rice.

Instructions

  1. 1

    Remove the pork loin from the refrigerator 30 minutes before cooking. Preheat your oven to 375°F (190°C). Pat the pork dry with paper towels on all sides — this is important for getting a proper sear.

  2. 2

    Make the garlic-herb paste: combine the minced garlic, rosemary, thyme, Dijon mustard, 1 tbsp of the olive oil, salt, pepper, onion powder, and smoked paprika in a small bowl. Stir into a thick paste. Rub this all over the entire pork loin — top, bottom, and all sides — pressing it gently into the meat.

  3. 3

    Heat the remaining 1 tbsp of olive oil in a large oven-safe skillet (cast iron or stainless steel work best) over medium-high heat until the oil shimmers and just begins to smoke. Carefully place the pork loin in the pan. Sear without moving for 3–4 minutes until a deep golden-brown crust forms on the bottom. Turn and sear the remaining sides for 2–3 minutes each — you want good color on all four sides.

  4. 4

    If doing a sheet-pan version, transfer the seared pork loin to a rimmed baking sheet. Toss the halved baby potatoes and broccoli or Brussels sprouts with olive oil, salt, and pepper and arrange them around the pork. If cooking pork only, leave it in the oven-safe skillet.

  5. 5

    Roast at 375°F until the thickest part of the loin registers 140°F–145°F on an instant-read thermometer. Start checking at the 40-minute mark. A 3 lb loin typically takes 45–55 minutes; a 4 lb loin takes 55–65 minutes. The pork loin is lean, so do not push past 145°F — it will continue cooking as it rests.

  6. 6

    Transfer the pork loin to a cutting board and tent loosely with foil. Let it rest for 10–15 minutes before slicing. Resting is non-negotiable with lean cuts like pork loin — the juices redistribute during this time. If you cut too early, the juices will pour out and the slices will be noticeably drier. If you added vegetables to the pan, return them to the oven while the pork rests if they need more time.

  7. 7

    Slice the pork loin crosswise into ½-inch to ¾-inch thick medallions. The slices should be slightly pink in the center and very juicy. The USDA updated safe pork temperature guidelines to 145°F in 2011, so a slight blush of pink is completely safe and desirable. Arrange the slices on a platter and spoon any pan juices over the top. Serve with roasted vegetables, applesauce, or a simple pan sauce made from the drippings.

Frequently Asked Questions

What is the difference between pork loin and pork tenderloin?+
Pork loin and pork tenderloin come from different parts of the pig and behave very differently in cooking. The pork loin is a wide, thick roast from the back of the pig — typically 3–5 lbs boneless, with a fat cap on top. It is lean but forgiving due to its size and is excellent for roasting. The pork tenderloin is a long, narrow, very lean muscle from just below the backbone — typically 1 to 1.5 lbs. It cooks much faster (20–25 minutes total) and is even leaner. They are not interchangeable in recipes — using tenderloin timing on a loin will result in a severely undercooked roast, and vice versa.
What temperature should you cook pork loin to?+
The USDA updated its safe minimum internal temperature for whole pork cuts (including pork loin roast) to 145°F in 2011, followed by a 3-minute rest. At 145°F, the pork will have a faint blush of pink in the center — this is completely safe and actually desirable, as it indicates the loin has not been overcooked. Pork loin is a lean cut, and once it goes above 155°F–160°F, it begins to dry out noticeably. Use an instant-read thermometer and pull it from the oven at 140°F–145°F, allowing carryover cooking during the rest period to finish the job.
How do you avoid drying out a pork loin roast?+
Three techniques make the biggest difference: searing first to build a crust that slows moisture loss, not overcooking past 145°F internal (the most common mistake), and resting the roast for at least 10–15 minutes tented with foil before slicing. Applying a mustard-based herb rub (as in this recipe) also helps — mustard acts as a binder and forms a protective layer during roasting. If you want extra insurance, brining the pork loin for 2–4 hours in a solution of 4 cups water and 3 tbsp salt before cooking adds significant moisture retention.
What are good leftover ideas for pork loin?+
Leftover pork loin is one of the most versatile proteins for the week ahead. Slice it thin for sandwiches or wraps with mustard and pickles. Dice or shred it into fried rice with eggs, frozen peas, soy sauce, and sesame oil. Slice into strips and add to stir fry. Chop and use as a filling in tacos or grain bowls with roasted vegetables and a drizzle of sauce. It also makes an excellent base for a quick ramen — slice thin, heat the broth, and add sliced pork, a soft-boiled egg, and ramen noodles.
How do you slice a pork loin roast?+
Always rest the pork loin for at least 10–15 minutes before slicing — cutting into it immediately causes the juices to run out. Use a sharp carving knife or chef's knife and slice crosswise (against the grain) into ½-inch to ¾-inch thick medallions. Thinner slices work well for sandwiches and stir fry; thicker slices hold up better for plating as a main dish. If the roast has a fat cap, you can leave it on for serving (the fat is flavorful) or trim it off before slicing. A carving fork or tongs to stabilize the roast while cutting will help keep the slices uniform.

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