There’s nothing better than coming home to a steaming bowl of French onion soup covered in melted cheese on a chilly evening. This comfort food classic is loaded with silky strands of caramelized onion swimming in a delectable broth. Then it’s topped with cheesy slices of French bread for one of the most satisfying soups you’ll ever tuck into. The only problem? It’s quite a labor-intensive dish.
Low and slow is usually the name of the game when it comes to caramelizing onions—and it still is for this recipe, only we’re letting the slow cooker do the heavy lifting. Making sure the onions don’t brown too quickly or stick to the bottom of a pan involves constant stirring. The Crockpot is the hands-free answer to a delicious, heart-warming French onion soup that doesn’t require you to hole up in your kitchen for hours.
With a few pantry staples, easily accessible ingredients and one trusty appliance, you’ll master our Crockpot French onion soup recipe and never make this soup another way.
Ingredients for Crockpot French Onion Soup
- Butter: You can’t caramelize onions for French onion soup without butter. We like high-fat European butter for this recipe, to get the best flavor, but lower-fat American butter will do if that’s what you have on hand.
- Onions: A blend of sweet onion (like Vidalia, Maui Sweets and Walla Walla Sweets) and sharp red onion is the secret to the best-ever French onion soup, but it’s important to use a two-to-one ratio of sweet to red, otherwise the flavor would be too intense.
- Condensed beef broth: Condensed, undiluted beef broth is also needed for the base of this soup. You can go the store-bought route with two cans, or make homemade beef broth and then boil it to reduce by half until it resembles more of a beef consomme.
- White wine: A dry white wine (like pinot grigio, chardonnay or sauvignon blanc) will help scrape up any remaining onion bits on the bottom of the slow cooker and keep the broth from being overly cloying from the sweetness of the caramelized onions. If you don’t have white wine or don’t want to use it, 3/4 cup of regular-strength beef broth is a perfectly fine substitute.
- Herbs: Fresh herbs like thyme and parsley are a nice complement to French onion soup with their earthy peppery notes. A dried bay leaf also works its magic by deepening the soup’s flavors and adding complexity (just remember to remove it before serving).
- Worcestershire sauce: The Worcestershire is good for a bit of umami—salty, sweet and spicy all at the same time.
- French bread: To use any other bread besides a baguette or crusty French bread would be criminal in this recipe for French onion soup in a slow cooker.
- Cheese: We love Gruyere for French onion soup. This French cheese is nutty, earthy and so good with the taste of caramelized onions in every bite, but you could also use Swiss cheese, raclette or Gouda as an alternative.
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