Slow-Cooker Mushroom Onion Butter Pot Roast Tips, FAQ & printable recipe

Tips for success

For the best flavor, use a good-quality beef bottom round roast that has some marbling. If the roast is very lean, you might want to add a splash of beef broth to the slow cooker to ensure there's enough liquid.

Also, don't be afraid to let the roast cook a little longer—the longer it cooks, the more tender it becomes.

When serving, spoon the jus generously over the meat and mushrooms. The jus is the best part—it's rich, buttery, and full of onion flavor.

If you have leftovers, the jus will solidify when chilled; just reheat it gently and it will become liquid again. You can also use the jus as a gravy for mashed potatoes or egg noodles.

Variations

• Add Carrots and Potatoes: For a one-pot meal, add 3 large carrots, peeled and cut into chunks, and 1 pound of baby potatoes to the slow cooker along with the mushrooms. They'll cook in the buttery jus and become tender and flavorful.
• Use Different Mushrooms: Cremini mushrooms are great, but you can also use a mix of wild mushrooms like shiitake, oyster, or baby bellas. Each variety adds its own earthy flavor and texture.
• Make It Spicy: Add a pinch of red pepper flakes or a diced jalapeño along with the onion soup mix for a subtle heat. The spice will infuse the jus and give the roast a nice kick.
• Herb-Roasted Version: Sprinkle fresh thyme or rosemary over the roast before cooking. The herbs will perfume the dish and add a fragrant note that complements the beef and mushrooms.

Storage and make-ahead

Fridge

Store leftovers in an airtight container in the fridge for up to 4 days. The meat will become even more flavorful as it sits.

Freezer

Freeze the cooked and shredded beef in an airtight container or freezer bag for up to 3 months. Thaw overnight in the refrigerator before reheating.

Reheat

Reheat leftovers in a saucepan over medium-low heat, stirring occasionally, until hot. Or microwave in 30-second intervals, stirring in between.

Store leftovers in an airtight container in the refrigerator for up to 4 days. The meat will keep well and actually tastes even better the next day as the flavors meld. Reheat gently in the microwave or on the stovetop, adding a splash of water or broth if needed to loosen the sauce.

This recipe is perfect for making ahead. You can assemble everything in the slow cooker insert the night before, cover, and refrigerate.

In the morning, place the insert in the slow cooker base and cook on LOW as directed. You can also cook the roast fully, then cool and refrigerate it for up to 3 days before reheating.

Serving ideas

Serve the pot roast over a bed of creamy mashed potatoes, egg noodles, or polenta. The rich jus soaks into the starch, making every bite comforting and satisfying. A side of crusty bread is also great for sopping up the extra sauce.

For a lighter option, serve the beef and mushrooms over a pile of sautéed greens or roasted vegetables.

The savory jus works beautifully with bitter greens like kale or broccoli rabe. And don't forget a glass of full-bodied red wine—it pairs perfectly with the rich, beefy flavors.

Frequently asked questions

Recipe card

Slow-Cooker Mushroom Onion Butter Pot Roast

Prep 10 minCook 8 hRest 10 minTotal 8 h 20 minServes 6

Ingredients

• 3 1/2 lb beef bottom round roast
• 1 oz dry onion soup mix (1 envelope)
• 8 oz cremini mushrooms, halved
• 1/2 cup salted butter (1 stick)

Instructions

1. Place the beef bottom round roast in the center of a 6-quart slow cooker. Sprinkle the dry onion soup mix evenly over the top of the roast. Scatter the halved cremini mushrooms around the sides of the roast, tucking them into the corners of the slow cooker.
2. Place the whole stick of salted butter directly on top of the seasoned roast. It will melt as the slow cooker heats, basting the meat and creating a rich, savory jus.
3. Cover the slow cooker and cook on LOW for 8 to 10 hours, until the beef is fork-tender and easily shreds. The internal temperature of the roast should reach at least 145°F (63°C) for safety, but for pot roast, cook until it's much more tender. Let it rest for 3 minutes before slicing.
4. After 8 hours, check the roast by inserting a fork into the thickest part. It should slide in with little resistance, and the meat should begin to pull apart. If not, continue cooking for another 1 to 2 hours. Let it rest for 3 minutes before slicing.
5. Turn off the slow cooker and let the roast rest in the liquid for at least 10 minutes. This allows the juices to redistribute, making the meat even more tender and flavorful.
6. Using two forks, shred the beef directly in the slow cooker, mixing it with the mushrooms and jus. Serve the hot beef and mushrooms over mashed potatoes or egg noodles, spooning extra jus over the top. Let it rest for 3 minutes before slicing.

Contains: milk, gluten, celery

Estimated nutrition per serving

Calories

420

Protein

35 g

Carbohydrates

8 g

Fat

28 g

Automatic estimate from the ingredient list, not laboratory-verified.