Name: Slow Cooker Beef Roast with Mushrooms and Onion Gravy
Prep time: 15 min
Cook time: PT-490264H26M49S
Total time: 9 h
Cuisine: American
Ingredients: 3–4 lb beef chuck roast; 2 yellow onions, sliced; 8 oz mushrooms (button or cremini), sliced; 3 cloves garlic, minced; 2 cups beef broth; 1 tbsp Worcestershire sauce; 1 tbsp soy sauce (optional); 1 tsp dried thyme or rosemary; 2 tbsp cornstarch (or flour); Salt and black pepper to taste; 1 tbsp olive oil or butter (for searing, optional)

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Slow Cooker Beef Roast with Mushrooms and Onion Gravy is a tender, flavorful dish that practically cooks itself. The beef becomes melt-in-your-mouth soft as it slowly simmers with savory onions, earthy mushrooms, and a rich gravy. I love how it fills the kitchen with cozy aromas and delivers comfort food at its finest — with barely any hands-on time.

Why You’ll Love This Recipe

I love how this meal transforms a simple beef roast into something deeply satisfying with just a few ingredients and a slow cooker. The mushrooms soak up the juices and become silky and savory, while the onions melt into the gravy, adding natural sweetness. It’s a set-it-and-forget-it kind of recipe that rewards me with a hearty, comforting dinner every time.

Ingredients

(Here’s a tip: Check out the full list of ingredients and measurements in the recipe card below.)

Beef chuck roast (or any well-marbled roast)
Yellow onions, sliced
Mushrooms (button or cremini), sliced
Garlic, minced
Beef broth
Worcestershire sauce
Soy sauce (optional, for umami depth)
Dried thyme or rosemary
Cornstarch or flour (for thickening)
Salt
Black pepper
Olive oil or butter (for searing, optional)

Directions

I start by seasoning the beef roast with salt and pepper. For extra flavor, I sear it in a hot skillet with oil until browned on all sides — this step is optional but worth it.
I place the sliced onions, mushrooms, and garlic into the bottom of the slow cooker.
I lay the roast on top of the vegetables.
I whisk together the beef broth, Worcestershire sauce, soy sauce (if using), and thyme, then pour it over the beef.
I cover and cook on low for 8–9 hours or high for 4–5 hours, until the roast is fork-tender.
About 30 minutes before serving, I mix cornstarch with a bit of water to make a slurry and stir it into the slow cooker to thicken the gravy.
I shred or slice the beef and stir it gently with the mushrooms, onions, and thickened gravy before serving.

Servings and timing

This recipe serves 6.
Prep time: 15 minutes
Cook time: 8–9 hours (on low)
Total time: About 9 hours

Variations

Sometimes I add carrots or baby potatoes to the slow cooker for a one-pot meal. If I want a deeper gravy, I replace some of the broth with red wine. For a creamier version, I stir in a spoonful of sour cream or heavy cream at the end. And if I don’t have mushrooms, I simply double up on the onions — they caramelize beautifully over time.

Storage/reheating

I store leftovers in an airtight container in the fridge for up to 4 days. The flavor actually improves after a day or two. To reheat, I warm it gently on the stove or microwave, adding a splash of broth if the gravy has thickened too much. This dish also freezes well — I portion it into freezer-safe containers and reheat when needed.

FAQs

Can I skip searing the beef?

Yes, but I like to sear it when I have time. It adds a nice depth of flavor and color to the final dish, though the slow cooker still makes it taste amazing without that step.

What’s the best cut of beef for this recipe?

I prefer chuck roast because it has the right amount of fat and connective tissue to become tender over long cooking. Brisket or round roast also work.

Can I use canned mushrooms?

Fresh mushrooms work best for texture and flavor, but in a pinch, I’ve used drained canned mushrooms. I just add them halfway through cooking so they don’t get too soft.

How can I make the gravy thicker?

I mix 1–2 tablespoons of cornstarch with cold water and stir it in about 30 minutes before serving. It thickens as it cooks. Flour works too, but I prefer cornstarch for a smoother finish.

What should I serve with it?

I usually serve this dish with mashed potatoes, egg noodles, or crusty bread to soak up the gravy. A side of roasted green beans or steamed broccoli rounds it out nicely.

Conclusion

Slow Cooker Beef Roast with Mushrooms and Onion Gravy is a comforting, hearty meal that’s full of flavor and incredibly easy to make. I love how the slow cooker does all the work, transforming a humble cut of beef into something rich, tender, and perfect for family dinners or lazy Sundays. With minimal prep and loads of taste, this dish is one I keep coming back to.