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This 5 lb pork sirloin roast recipe delivers tender, flavorful meat with a fragrant herb and garlic crust. My years at The Smoky Pig taught me that slow-roasting is key for perfect texture.
I start by searing the roast to lock in juices, then let it cook low and slow at 325°F. The herbs and garlic infuse every bite with deep, aromatic flavor.
The result is a juicy, tender roast with a beautiful crust that impresses every time. It’s a technique I’ve perfected over years of cooking for crowds.
Serve with roasted vegetables or mashed potatoes for a complete meal. This method never fails to deliver restaurant-quality results at home.
Ingredients for 5 lb pork sirloin roast
Sixteen ingredients for a restaurant-quality pork sirloin roast with herb and garlic crust.
| Ingredient | Amount | Notes |
|---|---|---|
| Pork Sirloin Roast 🥩 | 5 lb | Bone-in for extra flavor |
| Olive Oil 🫒 | 2 tbsp | Divided for searing and roasting |
| Kosher Salt 🧂 | 1 ½ tbsp | Diamond Crystal preferred |
| Black Pepper 🌶️ | 1 tbsp | Freshly ground preferred |
| Garlic Cloves 🧄 | 8 cloves | Minced for crust |
| Fresh Rosemary 🌿 | 2 tbsp | Chopped, stems removed |
| Fresh Thyme 🍃 | 2 tbsp | Leaves stripped from stems |
| Fresh Sage 🍃 | 1 tbsp | Finely chopped |
| Dijon Mustard 🟡 | 2 tbsp | For herb crust binding |
| Red Wine 🍷 | 1 cup | Dry variety for deglazing |
| Chicken Stock 🥣 | 1 cup | Low-sodium preferred |
| Unsalted Butter 🧈 | 2 tbsp | For basting |
| Onion 🧅 | 1 whole | Roughly chopped for roasting |
| Carrots 🥕 | 3 whole | Peeled and cut into chunks |
| Celery Stalks 🥬 | 2 whole | Cut into large pieces |
The pork sirloin is the star here. Bone-in roasts from Costco or your local butcher give the best flavor and texture—look for good marbling. I always grab mine from The Smoky Pig's supplier when I can. The herbs need to be fresh; dried won't give you that bright, aromatic punch. Rosemary, thyme, and sage are the holy trinity for this crust.
No fresh herbs? Dried at one-third the amount, but fresh really makes a difference here. Red wine can be swapped with extra chicken stock plus a splash of balsamic. Out of Dijon? Regular mustard works in a pinch. The bone-in pork is key though—boneless tends to dry out. If you can't find sirloin, pork shoulder works but has more fat.
The roast keeps beautifully—tastes even better the next day. Store in the fridge for up to 4 days, or freeze for 3 months. I always make extra; leftovers turn into incredible sandwiches or tacos. Just wrap tightly in foil before storing.
Why You'll Love This Recipe
- One Pan Wonder: I just rub the sirloin with olive oil, salt, pepper, and crushed garlic—then let the oven do the work.
- Garlic-Infused Bite: The roasted garlic cloves melt into the pork, giving every slice that rich, savory depth I crave.
- Feeds the Whole Crew: Honestly, this 5-pounder stretches for sandwiches, tacos, and dinners all week long.
- Budget-Friendly Feast: I get multiple meals from one affordable cut, and the leftovers taste even better the next day.
Step-by-step instructions for 5 lb pork sirloin roast
Here's the method that turns a simple roast into a showstopper every time.
Build the Herb and Garlic Crust
Pat the pork sirloin roast dry with paper towels, then place it on a clean surface. Rub the surface with 1 tablespoon olive oil, then season aggressively with 1.5 tbsp kosher salt and 1 tbsp black pepper. I like to press the seasoning into the meat so it adheres well.
In a small bowl, mix the 8 cloves minced garlic cloves, 2 tbsp fresh rosemary, 2 tbsp fresh thyme, 1 tbsp fresh sage, and 2 tbsp Dijon mustard until it forms a thick paste. Spread this mixture evenly over the entire surface of the roast. The mustard acts as a glue for the herbs, creating a flavorful crust.
Sear the Roast for Maximum Flavor
Heat the remaining 1 tablespoon olive oil in a large Dutch oven over medium-high heat. When it shimmers, carefully add the pork sirloin roast. Sear for 3-4 minutes per side until deeply browned. Don't move it around—let it develop a rich crust.
You'll know it's ready to flip when it releases easily from the pot. Once all sides are seared, transfer the roast to a plate temporarily. The fond (browned bits) left in the pot will become the base for your pan sauce.
Deglaze and Prepare the Roasting Liquid
Reduce heat to medium and add the 1 whole onion, 3 whole carrots, and 2 whole celery stalks to the Dutch oven. Cook for 2-3 minutes until they begin to soften. Pour in the 1 cup red wine and scrape up all those flavorful browned bits from the bottom.
Let the wine reduce by half, then add the 1 cup chicken stock. Return the pork sirloin roast to the pot, along with any accumulated juices. The liquid should come about halfway up the sides of the roast.
Slow-Roast to Perfection
Preheat your oven to 325°F. Once hot, transfer the Dutch oven to the oven and roast uncovered for 2 to 2.5 hours. Baste the pork with the cooking liquids every 30 minutes using the 2 tbsp unsalted butter to enhance the flavor and moisture.
You'll know it's done when an instant-read thermometer inserted into the thickest part reads 145°F. The meat should pull away from the bone slightly and the crust should be deep golden brown.
Rest and Serve
Transfer the pork sirloin roast to a cutting board and tent loosely with foil. Let it rest for 15-20 minutes before slicing. This resting period allows the juices to redistribute throughout the meat, ensuring every slice is moist and flavorful.
Strain the cooking liquids and skim off excess fat if desired. Serve the pork with the reduced pan juices spooned over the top. The meat should be tender with a beautifully herb-crusted exterior and aromatic juices.
Pro Tips For Making 5 Lb Pork Sirloin Roast
- Use a Meat Thermometer: I learned this the hard way—guessing doneness with a 5 lb roast leaves you with dry pork or undercooked meat. Aim for 145°F in the thickest part, then pull it off the heat.
- Slash the Fat Cap: Before seasoning, make shallow cuts in the fat cap about 1/4 inch apart. Sounds weird, but it works—the rendered fat bastes the meat while it roasts.
- Don’t Skip the Rest: Give it a solid 15-20 minutes under foil after roasting. I skip this when I'm lazy, but the dish is noticeably better when I don’t—the juices redistribute.
- Crush the Garlic: Smash the garlic cloves with the side of your knife before peeling. My grandmother swore by this, and she was right: it releases more flavor into the roast.
Troubleshooting perfect results
Uneven Cooking
If your pork sirloin roast is cooking unevenly, rotate the Dutch oven 180° halfway through roasting. This ensures even heat distribution in your oven. I learned this trick during my years at The Smoky Pig—it makes a noticeable difference.
Dry Crust
For a crust that's browning too quickly and drying out, tent the roast loosely with foil during the last 30-45 minutes of cooking. Alternatively, baste more frequently with the cooking liquids—every 20 minutes instead of 30. 💡
Low Internal Temp
If your roast isn't reaching 145°F after 2.5 hours, check your oven temperature with an oven thermometer. Many home ovens run 25-50°F cooler than set. Adjust accordingly and continue cooking until it reaches temperature.
Too Much Liquid
If your cooking liquid isn't reducing enough, remove the roast to a plate and simmer the liquid on the stovetop over medium-high heat for 5-10 minutes. This concentrates the flavors before returning the pork to serve.
Herbs Burning
If your herb crust is burning before the roast is done, lower your oven temperature to 300°F and extend cooking time. Also, ensure your Dutch oven isn't too close to the heating element. I've saved many a crust this way.
Tough Meat
If your pork sirloin roast turns out tough, it likely didn't reach the proper internal temperature. Always use a meat thermometer to confirm it hits 145°F. Also, be sure to let it rest for the full 15-20 minutes before slicing. 🔥
Nutrition facts
Frequently asked questions
Can I use boneless pork sirloin instead of bone-in?
Yes, but bone-in adds more flavor and helps keep the meat moist. For boneless, reduce cooking time by 15-20 minutes and monitor internal temperature closely. It may dry out faster without the bone.
Why do I need to rest the roast before slicing?
Resting allows juices to redistribute throughout the meat. Slicing too soon causes them to spill out, leaving the pork dry. 15-20 minutes is ideal for a 5 lb cut.
Can I make this in a slow cooker instead?
Sear first, then cook on low for 6-7 hours or high for 4-5 hours. Add liquid to prevent drying. The texture will be different but still delicious.
How do I know when it's done without a thermometer?
Press the meat: it should feel firm but still yield slightly. The crust will be deep golden brown, and juices should run clear. But a thermometer is most reliable.