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+ servings

Classic Onion Soup

Comforting and delicious
Prep Time25 minutes
Cook Time1 hour
Course: Appetizer, Main, Main Course, Soup
Cuisine: French
Keyword: classic french onion soup, main course soups, slow cooker carmaleized onions
Servings: 6
Calories: 375kcal


  • 4 cups sliced onions
  • 2 tbs butter
  • 1 tsp oil
  • 1/2 tsp sugar
  • 2 tbs flour
  • 2 quarts beef stock
  • 1/2 cup brandy or white wine/vermouth
  • 2 sprigs fresh thyme optional
  • 1 baguette or small French bread cut in 1/2-inch/1.25-cm slices
  • 6 slices Swiss cheese or provolone
  • 1/4 cup grated Parmesan cheese


  • Toast the baguette slices on a baking sheet in a 300F/150C oven until the edges just begin to get golden, about 10 minutes. Remove from oven and set aside
  • To caramelize the onions--melt butter over medium heat in a dutch oven. Add the oil. Add the sliced onions and stir to coat with the butter/oil. Saute the onions for about 5 minutes, stirring frequently, then stir in the sugar, cover the pot and cook for another 5 minutes (this is to cook the onions), stir occasionally. Remove the cover and cook, stirring frequently, until the onions are a nice deep brown. This will take about 30 minutes. Alternately, you may prepare the onions ahead by following this recipe beginning at the step 3 below where the flour is added--do not use additional butter/oil.
  • Stir the flour into the onions and cook for 2 minutes to cook the flour. Add the brandy or vermouth, scraping up the browned bits on the bottom of the pan. Add the stock, and thyme if using, bring to a boil then reduce heat to low and simmer for 30 minutes.
  • Place soup in 6 individual soup crocks (mine are 18 oz each). Set your broiler too high. Top each soup crock with 1 or 2 slices of baguette, place Swiss cheese over the bread and divide the Parmesan cheese evenly over each crock.
  • Place under the broiler and remove when cheese is melted, about 1 minute.


Serving: 1serving | Calories: 375kcal | Carbohydrates: 38g | Protein: 18g | Fat: 12g | Saturated Fat: 7g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 3g | Trans Fat: 1g | Cholesterol: 29mg | Sodium: 1014mg | Potassium: 808mg | Fiber: 3g | Sugar: 7g | Vitamin A: 296IU | Vitamin C: 8mg | Calcium: 264mg | Iron: 2mg