Cream of Onion Soup

Cream of Onion Soup

Here is a recipe for a truly luxurious and comforting Cream of Onion Soup. This is not the brothy, cheese-topped French Onion Soup, but rather a smooth, velvety, and deeply savory purée that makes for an elegant starter or a satisfying light meal.

Rich & Velvety Cream of Onion Soup

The secret to this soup's incredible depth of flavor is taking the time to slowly caramelize the onions. This process transforms their sharp bite into a sweet, jammy richness that forms the heart of the soup.

Yields: 4-6 servings

Prep time: 15 minutes

Cook time: 50-60 minutes

Ingredients

• 3 tbsp unsalted butter
• 2 tbsp olive oil
• 2 lbs (about 1 kg) yellow onions, thinly sliced
• 1 tsp salt, plus more to taste
• 1 tsp sugar (optional, to help with caramelization)
• 2-3 cloves garlic, minced
• 1 tsp fresh thyme leaves (or ½ tsp dried thyme)
• ¼ cup (30g) all-purpose flour
• ½ cup (120ml) dry white wine (like Sauvignon Blanc) or dry sherry
• 4 cups (32 oz / 950ml) chicken or vegetable broth, low-sodium preferred
• 1 cup (240ml) heavy cream or half-and-half
• ¼ tsp freshly ground black pepper, plus more to taste
• Pinch of ground nutmeg (optional, but recommended)

For Garnish (Optional):

Homemade croutons or store-bought

• Crispy fried onions
• Freshly snipped chives
• A drizzle of good olive oil or truffle oil
• A sprinkle of grated Gruyère or Parmesan cheese

Instructions

Caramelize the Onions: In a large pot or Dutch oven, melt the butter with the olive oil over medium-low heat. Add the thinly sliced onions, the 1 tsp of salt, and the optional sugar. Stir to coat the onions evenly. Cook, stirring every 5-10 minutes, for 30-40 minutes until the onions are very soft, deep golden brown, and sweet. Be patient—this is the most important step for building flavor. If they start to stick or burn, reduce the heat and add a splash of water.

Bloom the Aromatics: Add the minced garlic and fresh thyme to the pot with the caramelized onions. Cook for 1-2 minutes, stirring constantly, until fragrant.

Make the Roux: Sprinkle the flour over the onion mixture. Stir constantly for about 1-2 minutes to cook the raw flour taste out. This will form a thick paste (a roux) that will thicken the soup.

Deglaze the Pot: Slowly pour in the white wine or sherry, whisking continuously to scrape up any browned bits (the "fond") from the bottom of the pot. Let it bubble and simmer for 2-3 minutes until the liquid has reduced slightly.

Add Broth and Simmer: Gradually pour in the chicken or vegetable broth, whisking as you go to ensure a smooth, lump-free soup. Bring the mixture to a simmer, then reduce the heat to low, cover, and cook for another 15-20 minutes to allow all the flavors to meld.

Blend the Soup: Remove the pot from the heat and let it cool slightly for a few minutes.

Immersion Blender: Insert the blender directly into the pot and blend until the soup is completely smooth and velvety.

Standard Blender: Carefully ladle the soup into a blender in batches, never filling the blender more than halfway. Remove the small cap from the lid and cover the opening with a folded kitchen towel to allow steam to escape. Blend until perfectly smooth.

Finish with Cream: Return the blended soup to the pot (if using a standard blender). Place the pot over low heat. Stir in the heavy cream, the pinch of nutmeg, and the black pepper. Heat gently until the soup is warmed through, but do not let it boil, as this can cause the cream to separate.

Season and Serve: Taste the soup and add more salt and pepper as needed. Ladle into bowls and garnish with your choice of toppings.

Tips for Success & Variations

The Right Onions: Yellow onions are the best choice here as they become beautifully sweet when cooked. Sweet onions (like Vidalia) also work well.

For Extra Body: For an even thicker and creamier soup (without more cream), peel and dice one Yukon Gold potato and add it to the pot along with the onions in step 1. It will break down and blend into the soup, adding natural creaminess.

Make it Dairy-Free: Use olive oil instead of butter, vegetable broth, and a can of full-fat coconut milk instead of heavy cream. For the roux, you can use a gluten-free flour blend or omit the flour and thicken the soup at the end with a cornstarch slurry (1 tbsp cornstarch mixed with 2 tbsp cold water).

A Touch of Smokiness: Add a pinch of smoked paprika along with the garlic for a subtle, smoky depth.

Make-Ahead: This soup is a fantastic make-ahead dish. It can be stored in an airtight container in the refrigerator for up to 4 days. The flavors will continue to develop. Reheat gently on the stovetop. You can also freeze it for up to 3 months.

Enjoy this wonderfully comforting and elegant soup