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Slow-Cooked French Onion Soup

My husband and I love French onion soup, so I wondered if I could turn it into a less labor-intensive dish by altering my recipe to work in a slow cooker. The rich, cheesy result was an instant winner at home. —Ronda Eagle, Goose Creek, South Carolina
Slow-Cooked French Onion Soup
Slow-Cooked French Onion Soup Recipe photo by Taste of Home
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  • Total Time
    Prep: 30 min. Cook: 7 hours
  • Makes
    8 servings (2 quarts)

Ingredients

  • 2 tablespoons butter, cubed
  • 2 large sweet onions, halved and thinly sliced
  • 1 large red onion, halved and thinly sliced
  • 1/2 teaspoon coarsely ground pepper
  • 2 cans (10-1/2 ounces each) condensed beef broth, undiluted
  • 3 cups water
  • 3/4 cup white wine or regular-strength beef broth
  • 2 fresh thyme sprigs
  • 1 fresh parsley sprig, optional
  • 1 bay leaf
  • 2 teaspoons Worcestershire sauce
  • 16 slices French bread (1/4 inch thick)
  • 3/4 cup shredded Gruyere or Swiss cheese

Directions

  • Place butter in a 5-qt. slow cooker. Top with sweet and red onions; sprinkle with pepper. Cook, covered, on low until onions are tender, 5-6 hours.
  • Stir in broth, water, wine, herbs and Worcestershire sauce. Cook, covered, on low until flavors are blended, 2-3 hours. Remove herb sprigs and bay leaf.
  • To serve, preheat broiler. Place bread on a baking sheet; broil 4 in. from heat until lightly toasted, 1-2 minutes per side. Top bread with cheese; broil until cheese is melted, 1-2 minutes. Divide soup among eight bowls; top with cheese toasts and serve immediately.

Test Kitchen tips
  • Gruyere cheese is delicious in this recipe—its sweet, nutty flavor goes well with the oniony broth, and it melts wonderfully.
  • Toasting the bread with cheese separately, instead of broiling on top of the soup in crocks, prevents the underside of the bread from becoming soggy.
    • Nutrition Facts
    1 serving: 157 calories, 7g fat (4g saturated fat), 19mg cholesterol, 706mg sodium, 15g carbohydrate (6g sugars, 1g fiber), 7g protein.
    Every editorial product is independently selected, though we may be compensated or receive an affiliate commission if you buy something through our links.

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    Reviews

    Click stars to rate
    Average Rating:
    • Beyond
      Feb 17, 2021

      Wend more Tarragon? Not in this recipe?

    • Wendy
      Jan 25, 2021

      I happenstanced on this receipe. It is awesome! I did add some red wine and a little more of the tarragon. While same day serving is delicious- the following day were the bomb. Highly recommend.

    • dublinlab
      Mar 9, 2020

      This is amazing! I put the onions on for 6 hrs then added a can of dark beer instead of the wine. I let that sit overnight. Then completed the soup. Allowed it to cool again for the following day. I had the soup Hot, day old buns sliced and toasted, crocks ready and made up as people were ready. I;ll make this all the time. Janet. VFE

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