This juicy, tender and scrumptiously delicious, Lomo Relleno (Stuffed Pork Loin) is stuffed with aromatic spices, savory onions and mozzarella cheese; a perfect easy dish for any day of the week and makes an impressive dish to serve for any occasion or holiday!
Just like our Paleta de Cerdo and Pernil Asado, this pork loin meal feels special because there’s nothing quite like a perfectly cooked pork dish. This recipe for onion-stuffed pork loin combines the rich, savory flavors of caramelized onions, beef broth, balsamic vinegar, and creamy cheese, that creates a dish that is both elegant and comforting. Whether you’re hosting a dinner party or simply want to treat yourself to something delicious, this recipe is sure to impress with its tender, juicy pork and flavorful filling.
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Reasons to Love this Recipe
- Rich, Savory Flavors: The combination of caramelized onions, garlic, and herbs creates a deeply savory stuffing that complements the natural flavors of the pork loin.
- Tender and Juicy Meat: The stuffing helps keep the pork loin moist during cooking. As the onions release their juices, they infuse the meat with additional moisture and flavor creating a tender and succulent delicious dish!
- Cheese: Often, onion stuffed pork loin includes a layer of melted cheese, such as Mozzarella, Gruyère or Swiss, which adds a creamy addition that makes this dish even more irresistible and comforting.
- Elegant Presentation: When sliced, the pork loin reveals the beautiful layers of caramelized onions and cheese inside. It’s an elegant presentation which makes it an excellent choice for dinner parties or special occasions.
- Versatile and Adaptable: This dish can be easily adapted to suit different tastes and preferences. You can add mushrooms, spinach, or other vegetables to the stuffing to create your own unique version or use what you have on hand.
Ingredients
- Pork Loin – Choose a lean or slightly fatty cut of pork to ensure your stuffed pork loin turns out tender and juicy.
- Onions – Incorporate plenty of onions into the filling to achieve a deeply savory flavor. I used Vidalia onions for an even tastier filling.
- Beef Broth – Enhance the depth of flavor in the onions by cooking them with beef broth.
- Butter – Use pure butter to create a rich and savory filling.
- Balsamic Vinegar – Balsamic vinegar adds a touch of acidity and sweetness to the onion filling, that helps to balance the richness of the dish.
- Cheese – Use mozzarella, Gruyère, or Swiss to add a perfect layer of creaminess.
See my recipe card below for a complete list of the ingredients with measurements.
Substitutions and Variations
- Filling – Other delicious fillings include mushrooms, relleno de mofongo (mofongo filling), sausage, platanos fritos (sweet plantains) and spinach.
- Cheese – Although, I used mozzarella cheese, Gruyère is one of the best choices for filling pork loin.
- Gravy – Although optional, I love adding gravy to my pork loin. I’ve included a simple homemade gravy recipe using common pantry ingredients that most people have on hand.
- Vidalia Onions – While I prefer to use Vidalia onions for this recipe, red or white onions work well too.
Instructions
Step 1: Melt the butter in a skillet over medium heat (Image 1). Add the onions (Image 2).
Step 2: Add the beef broth, balsamic vinegar (Image 3) and and continue cooking until the onions are soft and browned (Image 4). Turn the heat off and set the onions aside to cool some until ready to use.
Step 3: Preheat oven to 400°F. Place the pork on a cutting board and cut lengthwise about one-third of the way from the bottom, stopping about 1 inch from the opposite end, being careful not to cut all the way through (Image 5).
Step 4: Open the loin and make a second horizontal cut on the thick side of the pork loin. Do not cut all the way through (Image 6).
Step 5: Season the inside of the pork loin with ½ of the garlic puree, salt, pepper, and oregano (Image 7). Top the left side of the loin with the cheese (Image 8).
Note: If the pork loin is too thick, cover with plastic wrap and pound until it is about ½ inch to a ⅓ inch thick.
Step 6: Top the onions on top of the cheese and in the middle (Image 9). Add more cheese on the right side of the loin (Image 10).
Step 7: Carefully roll the loin to completely enclose the filling (Image 11).
Step 8: Using the butchers twine, snugly secure the pork loin (Image 12).
Step 9: Add an extra piece of string lengthwise, then season the entire loin with the remaining garlic puree, salt, pepper, and oregano (Image 13).
Step 10: Add the pork loin back to the same skillet that the onions cooked in and sear on all sides until golden brown (Image 14 & 15).
Step 11: Transfer the pork loin to an oven-safe tray and place it in the oven. Cook for thirty minutes or until the internal temperature reaches 145°F.
What to Serve with Lomo Relleno
There are numerous delicious pairings for pork loin, ranging from mashed potatoes and roasted vegetables to rice. Here are a few tasty ideas I highly recommend.
- Arroz a la Jardinera (Garden Style Rice)
- Coles de Bruselas con Tocino (Brussel Sprouts with Bacon)
- Puerto Rican Arroz Blanco (White Rice) with Habichuelas Guisadas con Calabaza (Puerto Rican Stewed Beans with Pumpkin)
- Ensalada de Coditos con Jamón (Macaroni Pasta with Ham)
Expert Tips
- Pork Loin – When butterflying the pork loin, you might notice some sections are thicker than others. Use a mallet to even out these areas, ensuring uniform thickness for better cooking and presentation.
- Roasting – Be careful not to overcook the loin to avoid a dry pork roast.
- Searing – Be sure not to overlook searing the pork loin, as this step locks in the juices and imparts a beautiful golden color to the pork loin for presentation.
Recipe FAQs
Refrigerate in an air tight container or wrap in aluminum foil.
Consume the loin within three to four days.
If the loin is still whole, place in aluminum foil and bake at 375°F for 15-20 minutes.
If the loin is already sliced, reheat at 375°F for 10 minutes, ensuring to flip halfway through cooking. Alternatively, you can reheat in a pan over medium-low heat for five to seven minutes, flipping one or two times during cooking.
Other Pork Dishes You Will Love
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📖 Recipe
Lomo Relleno
Equipment
- large skillet large enough to fit loin
- butcher's twine
Ingredients
Pork
- 3 pounds pork loin rinsed under cool water and butterflied
- 3 tablespoon garlic puree or 4 garlic cloves finely minced
- ½ teaspoon dried oregano
- salt and pepper to taste
- 2 tablespoon vegetable or corn oil to roast the loin in skillet
Filling
- 2-3 large onions sliced thinly
- ½ cup beef stock or broth
- 2 tablespoon balsamic vinegar
- 4 tablespoon butter
- ½ lb mozzarella cheese thinly sliced or shredded
Simple Quick Gravy (Optional)
- 2 large beef bouillon
- 4 tablespoon flour
- 2¼ cups water
- 4 tablespoon butter
- ¼ teaspoon pepper
Instructions
Onion Filling
- In a skillet over medium-low heat, add the butter and let it melt.Note: Be careful not to burn the butter, as it will become bitter and affect the taste.Add the onions and cook until the onions are somewhat soft and translucent.
- Add the beef broth, followed by the balsamic vinegar and continue cooking until the onions are soft and browned. Turn the heat off and set the onions aside to cool some until ready to use.
Butterfly Pork
- Preheat oven to 400°F. Place the pork on a cutting board and cut lengthwise about one-third of the way from the bottom, stopping about 1 inch from the opposite end, being careful not to cut all the way through.
- Open the loin and make a second horizontal cut on the thick side of the pork loin. Do not cut all the way through.Note: If the pork loin is too thick, cover it with plastic wrap and pound until it is about ½ inch to a ⅓ inch thick.
Seasoning and Filling the Pork Loin
- Season the inside of the pork loin with the garlic puree, salt, pepper and oregano.
- Add the mozzarella slices vertically on the left side of the loin.
- Top the onion mixture on top of the mozzarella slices and in the middle section of the loin.
- Add the additional slices of mozzarella on the right side of the loin.
- Carefully roll the loin to completely enclose the filling.Using the butcher's twine, snugly secure the pork loin.Add an extra piece of string lengthwise, then season the entire loin with the remaining garlic puree, salt, pepper, and oregano.
Roast Loin in Skillet
- In a skillet over high heat, add the oil and heat for 30 seconds. Carefully add the loin and roast on all sides.
- Transfer the pork loin to an oven-safe baking dish and place it in the oven. Cook for 30-45 minutes or until the internal temperature reaches 150°F.
Simple Quick Gravy (Optional)
- Crumble cubes into boiling water to dissolve and set aside.
- Melt butter in a small saucepan. Slowly stir in the flour and whisk in with the butter.
- While stirring, slowly pour in the beef broth. It will start to thicken quickly. Add pepper to taste and salt if needed. Enjoy!
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