Slow-Cooker Cowboy Butter Flank Steak with Peppers Step-by-step instructions

Before you start

Before you start, set out your slow cooker and gather all the ingredients. Slice the flank steak into thin strips, about 1/4-inch thick, cutting against the grain for maximum tenderness. Slice the bell peppers into thick strips and cut the red onion into wedges.

If using a block of garlic-herb cowboy butter, cut it into a few pieces so it melts evenly. Have the au jus mix measured and ready. No need to preheat anything—the slow cooker does the work.

Instructions

Layer the raw ingredients

1. 1Layer the raw ingredients
   Place the sliced flank steak strips in the bottom of a 5-6 quart slow cooker, spreading them into an even layer. Scatter the bell pepper strips and red onion wedges over the beef. Place the garlic-herb cowboy butter pieces on top and sprinkle the dry au jus mix evenly over everything.
   Look for The slow cooker should be about half full with the beef and vegetables layered evenly.
   Tip For even cooking, try to slice the steak into similar-sized strips and keep the peppers and onions in large pieces so they don't break down too much.

The slow cooker should be filled with raw beef strips, peppers, and onions. The butter pieces sit on top, and the au jus mix is sprinkled evenly. The colors are vibrant—red, green, and yellow. The raw meat is cool to the touch. Everything is ready to cook.

Cook low and slow

2. 2Cook low and slow
   Cover the slow cooker and cook on low for 8 hours, or on high for 4-5 hours, until the beef is fork-tender and easily pulls apart. The sauce should be bubbling gently around the edges. Do not lift the lid during cooking unless checking for doneness near the end. Let it rest for 3 minutes before slicing.
   Look for The liquid will be bubbling slightly, and the meat will look deeply browned and tender when pierced with a fork.
   Safe temperature 145°F (63°C) internal temperature (steaks, chops and roasts)
   Tip Cooking on low gives the best texture for flank steak. If short on time, high heat works, but the meat may be slightly less tender.

After several hours, the slow cooker is bubbling gently. The butter has melted into a golden sauce, and the beef is visibly darkened and tender.

The aroma of garlic and herbs fills the kitchen. The meat should easily pull apart with a fork, and the vegetables are soft and glistening.

Rest and serve

3. 3Rest and serve
   Turn off the slow cooker and let the beef rest in the sauce for at least 3 minutes before serving. Use a slotted spoon to serve the steak and peppers over mashed potatoes or crusty bread, then spoon some of the buttery au jus over the top.
   Look for The meat should be tender enough to shred with a fork, and the sauce should be rich and glossy.
   Tip Letting the meat rest in the sauce keeps it moist and allows the flavors to meld before serving.

The beef rests in the hot sauce, soaking up even more flavor. The sauce is rich and glossy, coating the spoon. The meat is fork-tender and shreds easily. The peppers and onions are silky. The dish is ready to be served over mashed potatoes or bread, with extra sauce spooned on top.

Common mistakes

One common mistake is lifting the lid too often to check on the food. Every time you open the slow cooker, heat escapes and adds cooking time. Trust the process and only peek near the end of the suggested time.

Another mistake is slicing the steak too thick or with the grain, which makes it tough. Always slice against the grain. Also, resist the urge to add extra liquid—the meat and vegetables release moisture, and the butter and au jus create plenty of sauce.

How to tell it’s done

The dish is done when the beef is fork-tender and easily pulls apart. The internal temperature of the meat should reach at least 145°F (63°C) for food safety, but since it cooks for hours, it will be well above that.

The peppers and onions should be soft but not mushy, and the sauce should be bubbling and slightly thickened. Taste a piece of beef—it should be moist and full of buttery, savory flavor. If the meat is still chewy, continue cooking for another 30 minutes.

• Steaks, chops and roasts: 145°F (63°C) in the thickest part, then a 3-minute rest