Crockpot Gruyere Cream Mushroom Flank Steak Tips, FAQ & printable recipe

Tips for success

For the most tender beef, slice the flank steak very thin against the grain. This shortens the muscle fibers, so they fall apart easily after slow cooking.

If you have time, sear the beef in a hot skillet before adding it to the slow cooker — it adds a deeper, caramelized flavor, though it's not required. The recipe works beautifully as written, but a quick sear elevates it.

To make the sauce even richer, stir in a splash of heavy cream or a pat of butter during the last 30 minutes of cooking. If the sauce seems too thin, leave the lid off for the last 30 minutes to let it reduce.

For a thicker sauce, whisk in a cornstarch slurry (1 tablespoon cornstarch mixed with 2 tablespoons cold water) and cook for 10 more minutes. Adjust seasonings with salt and pepper at the end.

Variations

• Add Bacon: Cook 4 slices of bacon until crisp, crumble, and stir into the sauce during the last 30 minutes of cooking. The smoky flavor enhances the beef and mushrooms.
• Use Chicken: Swap the flank steak for boneless, skinless chicken thighs. Cook on low for 4 to 5 hours, until the chicken is tender and reaches 165°F (74°C).
• Make It Spicy: Add 1 teaspoon of red pepper flakes or a diced jalapeño along with the onions for a gentle heat that cuts through the creamy sauce.
• Vegetarian Version: Replace the beef with extra mushrooms and use a vegetarian cream of mushroom soup. Cook on low for 3 to 4 hours, until the mushrooms are tender.

Storage and make-ahead

Fridge

Store in an airtight container in the fridge for up to 4 days. The sauce may thicken; add a splash of broth or water when reheating.

Freezer

Freeze in a freezer-safe container for up to 3 months. Thaw overnight in the refrigerator before reheating gently.

Reheat

Reheat in a saucepan over medium-low heat, stirring occasionally, until hot. Add a little beef broth or water to loosen the sauce if needed.

Store leftovers in an airtight container in the refrigerator for up to 4 days. The sauce will thicken as it cools, so you may want to add a splash of beef broth or water when reheating.

Reheat gently on the stovetop or in the microwave until piping hot. The beef will remain tender, though it may lose a bit of its texture after reheating. This dish also freezes well.

You can assemble the entire slow cooker insert the night before: layer all the ingredients, cover, and refrigerate overnight. In the morning, place the insert in the slow cooker and cook as directed, adding about 30 minutes to the cooking time if starting from cold.

This makes it even easier to get dinner going on a busy morning. Alternatively, cook the full recipe, cool, and refrigerate for up to 3 days before reheating.

Serving ideas

Serve this flank steak hot, spooned over toasted garlic brioche or crusty bread to soak up the sauce. It also pairs well with mashed potatoes, egg noodles, or steamed rice. A simple green salad with a tangy vinaigrette balances the richness. For a low-carb option, serve over roasted vegetables or cauliflower mash.

Garnish with fresh chopped parsley or chives for a pop of color, if desired. The dish is satisfying on its own, but a side of sautéed greens or roasted asparagus makes a complete meal. For a special touch, top each serving with a few extra shavings of Gruyère before serving. The leftovers are just as delicious the next day.

Frequently asked questions

Recipe card

Crockpot Gruyere Cream Mushroom Flank Steak

Prep 10 minCook 6 hTotal 6 h 10 minServes 6

Ingredients

• 2 lb flank steak, thinly sliced against the grain
• 1 can (10.5 oz) condensed cream of mushroom soup
• 1 medium diced white onion
• 8 oz softened cream cheese
• 2 cups shredded aged Gruyère cheese
• 8 oz sliced cremini mushrooms
• 4 slices toasted garlic brioche slices

Instructions

1. Place the thinly sliced flank steak strips into the slow cooker basin, spreading them evenly across the bottom. Pour the condensed cream of mushroom soup over the beef, then scatter the diced white onion on top. Add the sliced cremini mushrooms, distributing them evenly.
2. Drop the softened cream cheese block on top of the beef mixture, then sprinkle the shredded Gruyère cheese evenly over everything. Do not stir — the layers will meld as the slow cooker heats.
3. Cover the slow cooker and cook on LOW for 6 to 8 hours, or on HIGH for 3 to 4 hours, until the beef is fork-tender and the sauce is bubbling. Stir gently once halfway through, if possible, to help the cheese melt into a smooth sauce. Let it rest for 3 minutes before slicing.
4. Turn off the slow cooker. Let the beef rest in the sauce for at least 3 minutes before serving. This allows the juices to redistribute and the meat to stay moist.
5. Place a slice of toasted garlic brioche on each plate. Ladle the hot beef and creamy mushroom sauce generously over the bread, letting the sauce soak in. Serve immediately.

Contains: gluten, milk, eggs

Estimated nutrition per serving

Calories

650

Protein

40 g

Carbohydrates

20 g

Fat

45 g

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