Vegetable-Beef Soup With a Top Hot and a Wink

Porcini mushrooms boost umami depth and balance the soup’s acidity.
Using strip steak, rather than a traditional stewing cut, ensures substantial bites of beef that cook to tenderness in a fraction of the time.
Dry sherry adds nuttiness and complexity to the broth.

The most important thing to know about Kansas City steak soup is that it is neither a chili nor a beef stew. If anything, it’s vegetable-beef soup with a top hat and a wink.

The dish originated at the Plaza III, a 1963 steakhouse that, over the decades, became better known for its soup than its steaks. Plaza III closed in 2018, but the soup survives: Variants are on menus at many Kansas City steakhouses today.

The original recipe remains a secret, despite numerous claims to have cracked the code in cookbooks and newspapers from Hartford to Orlando. But the elements of a good Kansas City steak soup are easily identifiable. The broth should be glossy and tangy—roux-thickened but not sludgy—and teeming with browned, chewy morsels of steak.

With those principles in mind, I quickly rejected both ground sirloin—common in copycat recipes, but not in KC steakhouses—and traditional stew cuts of beef like chuck roast, which evoke more pot roast than porterhouse.

After testing almost every cut in my butcher’s case, I landed on a clear answer. The best steak for a Kansas City steak soup is a Kansas City strip (New York strip for you coastal elites). Strip steaks have even marbling and fewer pockets of fat than other cuts, making them ideal for bite-size pieces with consistent flavor and chew.

Serious Eats / Qi Ai

Browning those pieces in butter leans further into the steakhouse vibe while lending the soup a nutty richness. To keep the focus on the steak, the veggies are simple: a standard mirepoix and a meaty portion of sliced mushrooms.

A quick note on beef broth, which is noticeably absent from the dish. Kenji has written about the superiority of store-bought chicken vs. beef stock before, but I nevertheless tested versions of this soup using beef broth, beef consomme, or a combination of beef and chicken stocks. Every version using store-bought beef broth had the dominant, bouillon-esque flavor of canned soup. If you have a few pounds of good soup bones in your freezer and want to make your own beef stock, I won’t stop you. But for most of us, chicken stock is going to be a better base. I promise, you won’t miss the beef, thanks to the other flavor boosters in this soup.

On to those flavor boosters: Dried porcini mushrooms, a frequent flyer in steakhouse dry rubs, are the umami backbone, bringing the acidity of the tomato-rich broth down to earth. Many recipes for Kansas City steak soup call for Kitchen Bouquet, a liquid seasoning that is mostly caramel color by volume with a dominant flavor of burnt marshmallow. I rejected it fairly early on in testing and experimented with other umami boosters: Maggi, Marmite, and soy sauce. They were delicious in their own right, but they resulted in a soup that tasted less like Kansas City steak soup and more like, well, Maggi, marmite, and soy sauce.

In the end, I reached for another “liquid seasoning” with midcentury vibes, one I already had in my fridge: A-1 Steak Sauce. While I wouldn’t necessarily recommend it for steaks, a small amount lends this soup extra body, color, and steakhouse twang. An equal amount of Worcestershire helps amp up the vinegar and molasses notes.

The other trick? A generous pour of sherry, an addition inspired by the steak soup at another classic KC steakhouse, The Golden Ox. Oloroso sherry offers toasty, prune-like flavors to complement the dish’s bolder, brassier notes. You can leave it out, but the soup won’t have the same depth.

It’s vegetable beef soup with a top hat and a wink, right? The sherry’s the top hat. The A-1’s the wink.