Slow Cooker Mushroom Butter Pork Roast

This slow cooker pork sirloin roast is the ultimate set-it-and-forget-it dinner. Just a few simple ingredients—pork, onion soup mix, mushrooms, and butter—come together in the slow cooker to create a tender, savory roast that falls apart at the touch of a fork. The onions and mushrooms melt into a rich, buttery sauce that coats every bite. Perfect for busy weeknights, this recipe requires just 10 minutes of prep and then lets the slow cooker do all the work.

There's something magical about a slow cooker meal that comes together with minimal effort. This pork sirloin roast is seasoned with dry onion soup mix, surrounded by cremini mushrooms, and topped with a stick of salted butter. As it cooks low and slow, the pork becomes melt-in-your-mouth tender, and the juices blend with the butter and soup mix to create a rich, savory gravy.

The best part? You literally dump everything into the slow cooker and walk away. Hours later, you come back to a bubbling pot of perfectly cooked pork and mushrooms, ready to serve. It's the kind of dinner that makes you look like a hero with almost zero effort.

Ingredients

Why this recipe works

Cooking the pork sirloin roast on LOW for 8 to 10 hours allows the collagen in the meat to break down slowly, turning a lean cut into tender, shreddable pork. The low, gentle heat also gives the mushrooms time to soften and release their earthy flavor, which melds with the onion soup mix and butter to create a deeply savory sauce. Unlike high-heat cooking, the slow cooker doesn't dry out the meat; instead, it keeps the roast moist and juicy, basting it in its own juices.

The combination of dry onion soup mix and salted butter is a classic flavor duo that needs no extra seasoning. The soup mix provides a concentrated blend of onion, salt, and herbs, while the butter adds richness and helps emulsify the pan juices into a silky sauce.

Because the ingredients are layered in the slow cooker, the flavors meld together without any extra steps. This is a true dump-and-go recipe, perfect for anyone who wants a delicious home-cooked meal without spending hours in the kitchen.

Notes and substitutions

Pork sirloin roast is a lean, boneless cut that works beautifully in the slow cooker. It's often labeled as 'pork sirloin roast' or 'pork sirloin tip roast' at the grocery store. If you can't find it, pork shoulder or pork butt are excellent substitutes, though they may need an extra hour or two of cooking time.

Cremini mushrooms, also known as baby bellas, have a deeper flavor than white button mushrooms and hold up well during long cooking. You can also use white button mushrooms if that's what you have on hand.

The dry onion soup mix is the key to this recipe's savory depth. It typically comes in a 1-ounce envelope, and you'll use the whole packet. If you prefer to avoid the additives in packaged soup mixes, you can make your own blend of onion powder, garlic powder, and dried herbs, but the flavor will be slightly different.

Salted butter is specified because it adds just the right amount of salt to the sauce; if you only have unsalted butter, add a pinch of salt to the pot before cooking.

• pork sirloin roast: pork shoulder or pork butt (increase cook time by 1-2 hours, until fork-tender)
• dry onion soup mix: 1 tablespoon onion powder plus 1 teaspoon garlic powder and 1 teaspoon dried parsley
• cremini mushrooms: white button mushrooms or baby bella mushrooms
• salted butter: unsalted butter plus 1/4 teaspoon salt

Equipment

• 6-quart slow cooker
• Measuring spoons
• Cutting board
• Chef's knife
• Serving spoon