London Broil Recipe Slow Cooker: Hands-Off Juicy Slices

This slow cooker method transforms tough cuts into juicy, tender London broil with minimal effort. The key is a flavorful marinade and low, steady heat.

After hours of slow cooking, you’ll have perfectly cooked beef that slices beautifully and stays moist. Serve it with mashed potatoes or roasted vegetables for a complete meal.

Ingredients for London Broil Recipe Slow Cooker

Transform tough beef into juicy, tender slices with these carefully selected ingredients.

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The beef cut is critical here. London broil traditionally refers to top round or flank steak—avoid leaner cuts like sirloin which can dry out. For best results, select a piece with visible marbling (about 1-inch thick). Costco and Whole Foods typically carry pre-cut options, but any well-stocked butcher counter will have what you need.

No Worcestershire? Coconut aminos work in a pinch (though flavor differs slightly). Out of red wine vinegar? Apple cider vinegar at the same amount substitutes well. The Dijon mustard can be swapped for whole-grain mustard if preferred. For the broth, homemade or high-quality store-bought makes a noticeable difference in depth of flavor.

Marinate the beef for 4-12 hours for maximum tenderness. Cooked London broil keeps 3-4 days refrigerated or 3 months frozen. Slice against the grain just before serving for the most tender results.

Step-by-Step Instructions for London Broil in a Slow Cooker

Here is the method to achieve tender, juicy slices with minimal hands-on effort.

Step 1: Prepare the Marinade

In a medium bowl, whisk together the 0.5 cup Soy Sauce, 2 tbsp Worcestershire Sauce, 2 tbsp Olive Oil, 2 tbsp Red Wine Vinegar, 2 tbsp Brown Sugar, 1 tbsp Dijon Mustard, 1 tsp Kosher Salt, 1 tsp Black Pepper, 1 tsp Onion Powder, and 1 tsp Smoked Paprika. The mixture should be smooth and well combined.

Add the 4 cloves Garlic Cloves, minced, and stir to distribute evenly. This marinade delivers a balance of savory, sweet, and tangy notes that will penetrate the 2 lb London Broil during the slow cooking process.

Step 2: Coat and Marinate the London Broil

Place the 2 lb London Broil in a large resealable plastic bag or shallow dish. Pour the prepared marinade over the meat, ensuring it is fully submerged. Massage the marinade into the surface of the meat to guarantee even coverage.

Seal the bag or cover the dish and refrigerate for at least 2 hours, though overnight marinating yields the most flavorful results. The meat will absorb the marinade, enhancing both tenderness and depth of flavor.

Step 3: Slow Cook to Juicy Perfection

Transfer the marinated London Broil and all the marinade to the slow cooker. Pour in the 0.5 cup Beef Broth to add additional moisture and richness. This liquid will prevent the meat from drying out during the extended cooking time.

Cover and cook on low heat for 6-8 hours or on high heat for 3-4 hours. The London Broil is done when it reaches an internal temperature of 145°F and the meat is fork-tender.

Resist the urge to lift the lid during cooking, as this releases heat and extends the cooking time. The slow, steady heat ensures the connective tissues break down, resulting in a juicy, tender final product.

Step 4: Rest and Slice

Once cooked, transfer the London Broil to a cutting board, reserving the cooking liquid for serving if desired. Tent the meat loosely with foil and let it rest for 10-15 minutes. This allows the juices to redistribute throughout the meat.

Slice thinly against the grain to maximize tenderness. The slices should be moist and flavorful, with a rich, caramelized exterior from the marinade. Serve immediately with the reserved cooking liquid spooned over the top for added moisture and depth.

Essential Equipment for This Recipe

Slow Cooker Choice

I recommend a 6-quart programmable slow cooker like the Crock-Pot Touchscreen for this recipe. It has precise temperature control and a timer function, ensuring your London broil cooks evenly without overcooking. 💡

Meat Thermometer

A digital instant-read thermometer is essential for checking the internal temperature. I use the ThermoWorks ThermoPop—it gives accurate readings in 3-4 seconds and is affordable for home cooks.

Cutting Tools

For slicing against the grain, a sharp 8-inch chef’s knife is ideal. I prefer Wüsthof or Victorinox brands—they maintain their edge well and provide the control needed for thin, even slices.

Marinade Prep

Use a large resealable plastic bag or shallow glass dish for marinating. The bag saves space in the fridge and ensures the marinade coats every surface. I reuse mine for up to 6 months before recycling.

Serving Essentials

A carving board with a groove catches juices while resting the meat. Pair it with a gravy boat for serving the reserved cooking liquid. These small touches make serving effortless. 🔥

Optional Upgrades

For extra browning, finish the cooked London broil under a broiler for 3-4 minutes before slicing. I use my Lodge cast iron skillet for this step—it handles high heat beautifully.

Frequently Asked Questions