Whole Pork Loin with Mashed Potatoes
Watch the Full Step-by-Step
- Chef's knife
- Large pot
- Colander
- Potato masher
INGREDIENTS
Pork:
- 2.5 pounds/1 kilogram whole pork loin
- 2 tablespoons Dijon or yellow mustard
- 2 tablespoons barbecue sauce
- 2 tablespoons olive oil
- 1 tablespoon soy sauce
- 1 teaspoon salt
- 1 teaspoon ground black pepper
- 1 teaspoon sweet paprika
- ½ teaspoon hot paprika or cayenne
- 1 teaspoon garlic powder
- 1 tablespoon Italian seasoning
- 3 ounces/85 grams unsalted butter
- 3 garlic cloves, minced
- 10 ounces/300 grams mushrooms, diced
Mashed potatoes:
- 2.5 pounds/1 kilogram Yukon Gold or russet potatoes, peeled and cut into chunks
- 5 ounces/150 grams unsalted butter
- Salt to taste
- ½ cup warm potato cooking water, as needed
INSTRUCTIONS
- Heat the oven to 300°F/150°C.
- In a bowl, whisk together the mustard, barbecue sauce, olive oil, soy sauce, salt, pepper, paprikas, garlic powder, and Italian seasoning.
- Line a baking dish with parchment paper and spread a thin layer of sauce on the bottom. Place the whole pork loin on top and coat thoroughly with the remaining sauce. Wrap tightly in the parchment, then cover securely with aluminum foil.
- Roast for 75–90 minutes, until the center reaches 135–140°F/57–60°C. Increase the oven to 350°F/180°C. Uncover, reserving the pan juices. Stir half the juices with 1 ounce/28 grams butter and spoon over the pork. Return to the oven and roast, uncovered, for 20–25 minutes, until the internal temperature reaches 145°F/65°C.
- Crush the garlic into the remaining pan juices. Scatter the mushrooms around the pork and spoon the garlic sauce over them. Roast for 8–10 minutes more, until the mushrooms are tender and lightly caramelized and the pork remains at 145°F/65°C.
- Let the pork rest for 10–15 minutes before slicing. Serve with the mushrooms and pan sauce.
- Meanwhile, place the potatoes in a large pot of salted water and bring to a boil. Cook until fork-tender, about 20 minutes. Drain, reserving some of the cooking water. Mash with the butter, adding warm cooking water as needed until smooth and creamy. Season to taste and serve alongside the pork.
FAQ
What is the best way to ensure a whole pork loin stays juicy during roasting?
start by bringing the meat to room temperature for 30 to 60 minutes before cooking. This helps it cook evenly from edge to center and prevents the outside from drying while the inside reaches temperature. Coating the pork with a flavorful marinade or sauce, like mustard, barbecue, and olive oil as in this recipe, also helps lock in moisture. Roasting at a lower temperature initially, such as 300°F/150°C, allows the fat and connective tissues to render slowly, keeping the meat tender.
Covering the pork in parchment and foil during this stage traps steam, further preventing moisture loss. After slow-roasting, finishing the whole pork loin uncovered at a higher temperature helps develop a golden crust without overcooking the interior. Resting the meat for at least 10 minutes after removing it from the oven lets the juices redistribute, ensuring each slice is moist and flavorful.
What are the best mushrooms to use with a whole pork loin roast?
Button or cremini mushrooms are excellent choices because they absorb sauces well and develop a slightly caramelized texture when roasted. Baby bella mushrooms offer a deeper, earthier flavor, which enhances the pork’s natural sweetness. Shiitake mushrooms can also work, providing an umami-rich punch that pairs nicely with a garlic and butter sauce.
Dice the mushrooms evenly so they cook at the same rate and place them around the pork in the last 10 minutes of roasting. Adding crushed garlic and pan juices over the mushrooms enhances their flavor and allows them to mingle with the pork’s natural drippings. Avoid very watery mushrooms like oyster or enoki, as they can release too much liquid and prevent caramelization, which is key for achieving the signature golden, savory topping for the whole pork loin.
What is the ideal resting time for a whole pork loin after roasting?
Ideally, let the meat rest for 10 to 15 minutes, loosely covered with foil to retain warmth. During this period, the muscle fibers relax and the redistributed juices settle throughout the pork, rather than spilling out when sliced immediately. Without resting, the whole pork loin can lose moisture quickly, resulting in dry slices and less flavorful meat.
Resting also allows residual heat to finish cooking the center gently, ensuring even doneness throughout. For larger pork loins, resting for up to 20 minutes may be necessary.
Can I prepare the sauce ahead of time?
Mixing the mustard, barbecue sauce, olive oil, soy sauce, and seasonings a few hours or even a day before roasting allows the flavors to meld, producing a richer coating for the meat. Store the sauce in a sealed container in the refrigerator until ready to use.
When applying, make sure the sauce comes to room temperature so it spreads evenly and does not cool the meat’s surface. Pre-preparing the sauce also saves time during the roasting process and ensures consistent seasoning throughout.
How can I prevent the mushrooms from becoming soggy?
Add the mushrooms only during the final 10 minutes of cooking so they roast rather than steam. Scatter them evenly around the pork rather than piling them on top, allowing hot air to circulate. Tossing the mushrooms lightly in a small amount of pan juices or oil enhances flavor without oversaturating them.
Avoid using mushrooms that are excessively wet or large; cut them into uniform pieces to ensure even cooking. If the pan releases too much liquid, carefully drain a little before adding mushrooms.
Can I brine a whole pork loin before roasting?
Brining a whole pork loin before roasting can enhance juiciness and flavor. A basic brine involves dissolving salt, sugar, and optional aromatics in water and submerging the pork for 2 to 6 hours in the refrigerator. Brining increases the pork’s water retention during roasting, producing a more tender and flavorful end result.
If you brine, reduce added salt in the seasoning or sauce to avoid oversalting. Pat the pork dry before applying the mustard-barbecue sauce mixture to ensure proper adhesion and browning. Brining slightly changes the texture, giving a more moist and cohesive meat while still allowing the slow roast and butter glaze steps to create a caramelized exterior.
How should I slice a whole pork loin to serve it neatly and retain moisture?
After roasting, allow the pork to rest for 10 minutes to let juices redistribute. Use a sharp chef’s knife and make even slices about ½ inch thick across the grain of the meat. Slicing against the grain shortens the muscle fibers, making each bite tender and easier to chew.
Keep the slices uniform so they retain heat and look consistent on a serving platter. Avoid cutting immediately after removing from the oven, as this causes the juices to escape and the pork to dry. Arrange slices with a slight overlap, and spoon pan sauce and mushrooms over them to enhance moisture and flavor.
What is the best way to store leftovers from a whole pork loin roast?
Allow the meat to cool slightly at room temperature for no more than two hours, then transfer to an airtight container. Refrigerate at 40°F/4°C or below for up to three to four days. If you plan to keep it longer, wrap slices tightly in foil or plastic wrap and place in a freezer-safe bag, then freeze for up to three months. When storing, keep the mushrooms and pan sauce separate if possible to prevent the meat from becoming overly soggy.
How should I reheat leftover whole pork loin without drying it out?
Preheat the oven to 275°F/135°C and place slices in a baking dish. Add a small amount of pan juices, broth, or water, then cover tightly with foil to trap steam. Heat until the internal temperature reaches 140–145°F/60–63°C, typically 15–20 minutes depending on thickness. Avoid microwaving at high power, as it can cause uneven heating and dry out the meat. For smaller slices, reheating in a skillet over low heat with a splash of sauce works well.
Can I use a different cut of pork?
Pork tenderloin is leaner and smaller, so it will cook faster and requires careful monitoring to avoid drying. Bone-in pork loin or rib roast can also be used; these cuts offer similar flavor and moisture but may need slightly longer cooking times.
When substituting, maintain the low-and-slow initial roasting to ensure even cooking and use a thermometer to reach the recommended internal temperature of 145°F/63°C. Seasoning and pan sauce steps remain the same, though leaner cuts may benefit from additional butter or sauce to retain juiciness.
How can I prepare a whole pork loin roast ahead of time?
Start by seasoning and marinating the meat, or even assembling the butter glaze and mushroom topping in advance. You can pre-cut the mushrooms and store them in the refrigerator until roasting.
The pork can be wrapped in parchment and foil, then refrigerated for up to 24 hours before cooking. Bring it to room temperature before placing it in the oven to ensure even cooking. The low-and-slow roasting method still applies, and finishing the glaze and mushrooms immediately before serving preserves freshness and flavor.
