Crockpot Mushroom Dijon Pork Sirloin Roast

This slow cooker pork sirloin roast is the ultimate set-it-and-forget-it dinner. With just a handful of pantry staples—onion soup mix, mushrooms, sour cream, Dijon, and au jus—you get a rich, creamy, savory dish that tastes like you simmered it all day. The pork comes out so tender it shreds at the touch of a fork, and the gravy is perfect over rice.

This recipe turns an affordable pork sirloin roast into a melt-in-your-mouth meal with minimal effort. The combination of savory onion soup mix, earthy cremini mushrooms, tangy Dijon mustard, and velvety sour cream creates a luscious gravy that clings to every strand of pork.

It's a true dump-and-go slow cooker dinner that delivers big flavor with almost no hands-on time.

Ingredients

Why this recipe works

Slow cooking is the secret to transforming a lean cut like pork sirloin into fork-tender perfection. The low, gentle heat breaks down the connective tissue, allowing the meat to become so tender it shreds effortlessly.

Cooking it low and slow also gives the flavors time to meld and deepen, creating a gravy that's far more complex than the sum of its ingredients.

The combination of sour cream and Dijon mustard adds both richness and brightness to the finished dish. The mustard cuts through the creaminess with a tangy kick, while the onion soup mix provides a savory backbone that pairs beautifully with the mushrooms. The result is a balanced, hearty sauce that elevates the pork without overpowering it.

Notes and substitutions

Pork sirloin roast is a lean, affordable cut that benefits from long, moist cooking.

If you prefer, you can substitute a boneless pork shoulder or butt for even more richness—just increase the cooking time by an hour or two, as these cuts have more fat and connective tissue. The mushrooms add an earthy depth, but white button mushrooms work just as well.

For the au jus, use a good-quality store-bought version or substitute beef broth for a lighter sauce.

Whole-grain Dijon mustard provides a lovely texture and a more pronounced mustard flavor; if you only have smooth Dijon, add a teaspoon more to compensate. The sour cream should be full-fat for the best richness, though reduced-fat will work in a pinch.

• pork sirloin roast: boneless pork shoulder or pork butt (will be even more tender)
• cremini mushrooms: white button mushrooms or baby bellas
• whole-grain Dijon mustard: smooth Dijon mustard (add a little extra for the same punch)
• au jus: beef broth or chicken broth (add 1 tsp Worcestershire for depth)

Equipment

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