Dinner · Part 3 of 3: Tips & recipe card

Cowboy Butter Green Bean Flank Steak Crockpot Dinner Tips, FAQ & printable recipe

Name: Cowboy Butter Green Bean Flank Steak Crockpot Dinner
Prep time: 10 min
Cook time: 8 h
Total time: 8 h 10 min
Cuisine: American
Ingredients: 2 lb flank steak, thinly sliced against the grain; 1 lb fresh green beans, trimmed; 1 1/2 lb russet potatoes, diced into 1-inch cubes; 2 sticks garlic-herb cowboy butter, sliced; 1 oz au jus mix

By Clara Weller · Oct 28, 2026

Slow cooker filled with tender flank steak, green beans, and potatoes in a golden butter au jus

Prep: 10 min
Cook: 8 h
Total: 8 h 10 min
Serves: 6

Tips for success

For the most tender flank steak, slice it as thinly as possible against the grain before adding to the slow cooker. This increases the surface area and allows the meat to break down faster.

If you have time, searing the steak strips in a hot skillet before adding them adds extra depth, but it's completely optional — the recipe works beautifully without it.

Don't skip the mashed potatoes — they're the perfect canvas for the rich gravy. The creamy texture balances the bold flavors of the beef and au jus.

If you want to lighten the dish, serve it over rice or egg noodles instead. Leftover gravy is fantastic spooned over roasted vegetables or used as a dipping sauce for crusty bread.

Variations

Add Mushrooms: Add 8 oz sliced cremini mushrooms along with the green beans. They will release moisture and add an earthy depth to the gravy. No need to adjust the liquid — the au jus and butter provide enough.
Spicy Kick: Stir 1-2 teaspoons of crushed red pepper flakes or a minced jalapeño into the au jus mix before sprinkling over the meat. This adds a subtle heat that balances the rich butter. Serve with extra peppers on the side for those who want more.
Use Chuck Roast: Swap the flank steak for 2 lb chuck roast, cut into 1-inch chunks. The extra marbling makes the meat even more fork-tender. Increase the cook time to 9 hours on LOW for optimal tenderness.
Vegetable Swap: Replace the green beans with 2 cups of frozen peas added during the last 30 minutes of cooking. The peas stay bright and sweet, and they don't get mushy. Keep the potatoes as is.

Storage and make-ahead

Fridge: Store leftovers in an airtight container in the refrigerator for up to 4 days. The gravy will thicken when cold; add a splash of broth when reheating.
Freezer: Freeze cooled leftovers in a freezer-safe container for up to 3 months. Thaw overnight in the refrigerator before reheating gently on the stovetop.
Reheat: Reheat in a saucepan over medium-low heat, stirring occasionally, until hot and bubbling. Add a little beef broth or water if the gravy is too thick.

Store leftovers in an airtight container in the refrigerator for up to 4 days. The flavors will continue to meld, making it even more delicious the next day. Reheat gently on the stovetop or in the microwave, adding a splash of beef broth if the gravy has thickened too much.

This recipe is naturally make-ahead friendly. You can assemble the raw ingredients in the slow cooker insert the night before, cover, and refrigerate.

In the morning, place the insert in the slow cooker and cook as directed. If you do this, add about 30 minutes to the cook time to account for the cold start.

Serving ideas

Serve the beef and vegetables over a generous scoop of creamy mashed potatoes, then ladle the garlic-herb butter au jus over the top.

The gravy soaks into the potatoes and ties everything together. A sprinkle of fresh parsley or chives adds color, but it's optional — the dish is already packed with flavor.

For a complete meal, add a side of crusty bread or a simple green salad. The bread is perfect for soaking up any extra gravy. This dish also works well over rice, egg noodles, or polenta. Pair it with a full-bodied red wine, like a Zinfandel or Syrah, to complement the rich, savory flavors.

Frequently asked questions

Can this recipe be made with chicken instead of beef?

Yes, boneless, skinless chicken thighs can be substituted for the flank steak. Use about 2 pounds and cook on LOW for 6-7 hours, until the chicken reaches 165°F (74°C). The cook time is shorter because chicken cooks faster than beef. Be sure to check the temperature to ensure it's safe.

Why does the gravy sometimes turn out thin?

The gravy may be thin if the slow cooker was on HIGH for too long or if there's excess condensation from lifting the lid. To thicken it, mix 2 tablespoons cornstarch with 2 tablespoons cold water and stir into the hot liquid during the last 30 minutes of cooking. Let it simmer uncovered to reduce.

Can this dish be cooked on HIGH instead of LOW?

Yes, you can cook it on HIGH for about 4 hours instead of 8 hours on LOW. However, the beef may be slightly less tender, and the vegetables might not absorb as much flavor. Always check the internal temperature of the meat before serving.

What can be used instead of au jus mix?

If you don't have au jus mix, you can use a packet of brown gravy mix or a beef bouillon cube dissolved in 1 cup of hot water. For a homemade version, combine 1 teaspoon beef base with 1/2 teaspoon garlic powder and 1/2 teaspoon onion powder. Adjust salt to taste.

Can the leftovers be frozen?

Yes, leftovers freeze well for up to 3 months. Cool the dish completely, then transfer to a freezer-safe container. Thaw overnight in the refrigerator and reheat gently on the stovetop or in the microwave. The gravy may separate slightly after freezing, but stirring while reheating will bring it back together.

Recipe card

Cowboy Butter Green Bean Flank Steak Crockpot Dinner

Prep 10 minCook 8 hTotal 8 h 10 minServes 6

Ingredients

2 lb flank steak, thinly sliced against the grain
1 lb fresh green beans, trimmed
1 1/2 lb russet potatoes, diced into 1-inch cubes
2 sticks garlic-herb cowboy butter, sliced
1 oz au jus mix

Instructions

Place the sliced flank steak strips in an even layer at the bottom of a 6-quart slow cooker. Scatter the trimmed green beans and diced russet potatoes over the beef. Arrange the slices of garlic-herb cowboy butter on top, then sprinkle the au jus mix evenly over everything.
Cover the slow cooker with its lid. Cook on LOW for 8 hours, or on HIGH for 4 hours, until the beef is fork-tender and easily shreds or cuts with a spoon. The potatoes should be soft and the green beans tender but not mushy. Let it rest for 3 minutes before slicing.
After the cook time, use an instant-read thermometer to check the thickest piece of flank steak. It should register at least 145°F (63°C). If not, continue cooking in 15-minute increments until it reaches the safe temperature. The meat will be very tender and may shred easily. Let it rest for 3 minutes before slicing.
Turn off the slow cooker and let the meat rest in the cooking liquid for at least 3 minutes before serving. This allows the juices to redistribute and keeps the beef moist and flavorful.
Spoon the beef, green beans, and potatoes over creamy whipped mashed potatoes on a dinner plate. Ladle plenty of the garlic-herb butter au jus over the top so every bite is coated in the rich, savory gravy.

Contains: milk, gluten

Estimated nutrition per serving

Calories: 520
Protein: 38 g
Carbohydrates: 32 g
Fat: 28 g

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

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This recipe is based on a short cooking video and is published under the pen name Clara Weller. It was checked before publication, but errors can slip through. Nutrition, when shown, is an estimate. Read more in our editorial policy and on our food safety page.