London broil is a classic dish that features a marinated flank steak cooked to perfection and sliced thinly against the grain. While traditionally cooked on a grill or broiled in the oven, using a slow cooker can result in a tender and flavorful London broil with minimal effort. In this recipe, we’ll show you how to make London broil in the slow cooker, creating a delicious and convenient meal that’s perfect for busy weeknights or weekend gatherings.
Ingredients for Slow Cooker London Broil
- 2 pounds flank steak
- 1/2 cup soy sauce
- 1/4 cup Worcestershire sauce
- 2 tablespoons balsamic vinegar
- 2 tablespoons honey
- 4 cloves garlic, minced
- 1 teaspoon onion powder
- 1 teaspoon black pepper
- 1/2 teaspoon smoked paprika
- 1/2 teaspoon dried thyme
- 1/2 teaspoon dried rosemary
- 1/4 teaspoon red pepper flakes (optional)
- 1/4 cup water
- 2 tablespoons cornstarch
- Chopped fresh parsley, for garnish
How to Make Slow Cooker London Broil
Step 1: Prepare the Marinade
- In a small bowl, whisk together the soy sauce, Worcestershire sauce, balsamic vinegar, honey, minced garlic, onion powder, black pepper, smoked paprika, dried thyme, dried rosemary, and red pepper flakes (if using).
Step 2: Marinate the Flank Steak
- Place the flank steak in a large resealable plastic bag or shallow dish.
- Pour the marinade over the steak, making sure it is evenly coated.
- Seal the bag or cover the dish with plastic wrap and refrigerate for at least 4 hours, or overnight, turning the steak occasionally to ensure even marinating.
Step 3: Cook in the Slow Cooker
- Remove the marinated flank steak from the refrigerator and let it come to room temperature for about 30 minutes.
- Place the steak and marinade in the slow cooker. Add 1/4 cup of water to the slow cooker.
- Cover and cook on low for 6-8 hours, or until the steak is tender and easily shreds with a fork.
Step 4: Thicken the Sauce (Optional)
- In a small bowl, mix 2 tablespoons of cornstarch with 2 tablespoons of cold water to create a slurry.
- Stir the slurry into the cooking liquid in the slow cooker.
- Cook on high for an additional 15-20 minutes, or until the sauce has thickened.
Step 5: Serve
- Remove the steak from the slow cooker and let it rest for a few minutes before slicing thinly against the grain.
- Serve the sliced London broil with the thickened sauce spooned over the top.
- Garnish with chopped fresh parsley, if desired.
About the Main Ingredients
Flank Steak
Flank steak is a lean and flavorful cut of beef that benefits from slow cooking. It is ideal for London broil because it can be tough if not cooked properly but becomes tender and juicy when cooked low and slow.
Soy Sauce
Soy sauce adds savory depth to the marinade and helps tenderize the flank steak. Use low-sodium soy sauce if you prefer a less salty dish.
Worcestershire Sauce
Worcestershire sauce adds richness and umami flavor to the marinade. It complements the other flavors and helps tenderize the meat.
Balsamic Vinegar
Balsamic vinegar adds a hint of sweetness and acidity to the marinade, balancing the flavors and adding depth to the dish.
Honey
Honey adds sweetness to the marinade, helping to balance the savory and acidic flavors. It also helps caramelize the steak as it cooks.
Garlic and Spices
Garlic, onion powder, black pepper, smoked paprika, dried thyme, dried rosemary, and red pepper flakes add layers of flavor to the marinade, making the London broil aromatic and delicious.
