Slow Cooker Sour Cream Stroganoff Flank Steak

This slow cooker dinner is the definition of set-it-and-forget-it. Two pounds of flank steak strips, pearl onions, carrots, sour cream, and a packet of brown gravy mix go into the crock in the morning.

By dinner, the beef is fork-tender and the sauce is a velvety, mahogany stroganoff. Spoon it over buttered egg noodles for a hearty, comforting meal that feels like it simmered all day — because it did.

There are slow cooker recipes that require browning, layering, and fussing, and then there are dump dinners like this one. The ingredients go in raw, the slow cooker does the work, and the result is a deeply savory, creamy beef stroganoff with sweet pearl onions and carrots.

The brown gravy mix thickens the sauce as it cooks, while the sour cream melts into a rich, tangy gravy. Serve it over wide egg noodles to catch every drop.

Ingredients

Why this recipe works

The slow cooker's low, moist heat breaks down the connective tissue in flank steak, turning a lean cut into spoon-tender strips. Because the beef is sliced thinly against the grain, it cooks evenly and stays tender rather than chewy.

The sour cream and gravy mix create a sauce that thickens naturally as the slow cooker simmers, so there is no need for a roux or extra thickening at the end.

Layering the ingredients without stirring is intentional. The gravy mix sits on top and slowly dissolves into the liquid released by the beef and vegetables, creating a smooth, lump-free sauce. The pearl onions and carrots hold their shape and sweetness, balancing the rich, savory gravy. This is a one-pot dinner that delivers deep flavor with almost zero active time.

Notes and substitutions

Flank steak is the star here — slice it thinly against the grain for the most tender result. If you prefer, use sirloin or round steak, but avoid stew meat, which can become dry.

Pearl onions add a mild, sweet onion flavor; if you cannot find them, use a small yellow onion cut into wedges. Crinkle-cut carrots are classic in this dish, but regular sliced carrots work just as well.

Brown gravy mix is the shortcut that makes this recipe come together in minutes. Look for a packet that contains just seasonings and thickener, not a lot of added salt. Full-fat sour cream is best — low-fat versions can curdle more easily. For a lighter option, use plain whole-milk yogurt, but avoid Greek yogurt, which is too thick and tart for this sauce.

• flank steak: sirloin or round steak, thinly sliced
• pearl onions: 1 small yellow onion, cut into wedges
• brown gravy mix: 1 tablespoon cornstarch mixed with 1 cup beef broth
• sour cream: plain whole-milk yogurt (not Greek, to avoid curdling)

Equipment

• 6-quart or larger slow cooker
• Large skillet or pot for noodles
• Cutting board and sharp knife
• Measuring cups and spoons
• Serving spoon