French Onion Soup {Easy Slow Cooker Recipe} (2024)

FAQs

How do you deepen the flavor of French onion soup? ›

A few sprigs of thyme and a bay leaf elevate the soup even more, but I take it a step further, adding a splash of fish sauce for complexity and depth—don't worry, it won't taste fishy—and a hit of cider vinegar to balance some of that oniony sweetness.

It can be nice to cook the onions beforehand, as the flavour is different to when you put them in raw, but experiment both ways as you may find you prefer one. It can also be good to brown meat to give it some colour, but again, this is not essential.

What is the Difference Between Onion Soup and French Onion Soup? French onion soup is always made with beef stock. Other onion soups can be made with chicken, vegetable, or beef stock. Additionally, French onion soup typically contains wine or sherry, which isn't typical or necessary in other onion soups.

That's because the low, slow style of cooking lets the flavors simmer together for hours, creating a much richer and more flavorful meal.

The caramelized onions for this soup cook more quickly due to a pinch of baking soda but still have that deep, slow-cooked flavor. Topping the soup with hot, cheesy toasts prepared while the soup simmers, eliminates the need to bake the soup in specialty French onion soup bowls.

The key to good French onion soup is to cook the onions so long that they threaten to melt into a viscous, dark brown paste, à la Marmite. As has already been extensively reported in Slate, there are no shortcuts when you're caramelizing onions; it always takes at least an hour, usually longer.

The difference between "High" and "Low" on slow cookers seems to differ with every brand and model. One thing that is consistent, though, is that food takes seven to eight hours to reach a simmer point (around 210°) on low; versus three to four hours on high.

If you cook red onion with alkaline foods, such as nuts, lentils, and some vegetables, those anthocyanins revert to their blue hue. The same is true of red cabbage. To maintain the red hue, add a little acid, such as a splash of vinegar or a squeeze of lemon juice.

It's almost impossible to overcook these onions, but I've found that 10 hours makes soft, lightly browned onions that still have a bit of bite.

This soup traditionally is made with beef stock, though sometimes a good beef stock can be hard to come by and expensive to make. If you use boxed stock, taste it first! If you don't like the taste, don't use it. (If you cook a lot of beef or beef roasts, save the scraps and freeze them to make a stock with later.)

Why is French onion soup so good? ›

French onion soup is the ultimate comfort food. Onions get slowly cooked until sweet and caramelized, then simmered in rich broth until they're practically falling apart. To finish it off, toasted bread is added to give it that lovable crisp-gone-soggy texture and a generous amount of Gruyère cheese is melted on top.

Editor's Tip: Can you overcook soup in a slow cooker? It's a common question—and the short answer is yes. Ingredients like veggies, pasta and rice can get very mushy if left in the slow cooker too long. Many meats will toughen, too.

Most appliances will automatically shut off after 20 or so hours on this setting, but you shouldn't leave food in a slow cooker for an extended length of time. The general rule of thumb is that 2-4 hours is the maximum length of time you can leave food in a slow cooker on warm.

That varies by what's inside the slow cooker and also by the appliance's setting and model, the experts say. Most recipes for all-day cooking call for 6 to 8 hours on low. Quality- (and safety-) wise, another 1 to 2 hours in 'keep warm' mode won't mess things up.

Infusing the soup with a richer taste is as easy as quickly sauteing crushed garlic before pouring the soup in. Some soft, buttery garlic sauteed in earthy olive oil is the perfect addition to enrich canned French onion soup.

Use fresh vegetables, high-quality meats or broth, and fresh herbs to add depth of flavor. Add acidity: A squeeze of lemon or lime juice, a dash of vinegar, or a splash of wine can brighten the flavors of a soup and make it taste more complex.

Herbs and sources add flavor, aroma, and intensity to the soup broth. You can pick fresh or dried herbs like basil for tomato-based soups or fresh parsley for clear broths. You may also add more spices like turmeric, ground ginger, ground paprika, or nutmeg for a touch of spice and color to your soup broth.