Creamy Caramelized Onion Soup

Slow-browned onions blended into a smooth, lightly creamy soup enriched with butter and milk.

By Moow Editorial ·

Smooth caramelized onion soup in a serving bowl
Photo: Valeria Boltneva · Pexels License via Pexels · cropped by Moow
  • Cook the onions slowly until evenly amber; rushing this stage leaves the soup sharp instead of sweet.

At a glance

Read through the method once, then prep the ingredients in the order listed.

  • Yield: 4 bowls
  • Prep time: 40 minutes
  • Cook time: 40 minutes
For the most consistent result, use the listed weights when available; household measures are rounded.

Estimated nutrition per serving

Serving basis: One serving from the final reviewed yield of 4 bowls.

  • Calories: 190 kcal
  • Protein: 2 g
  • Carbohydrates: 11 g
  • Fat: 16 g
  • Sodium: 624 mg
Estimated from the listed ingredients and serving yield using USDA FoodData Central. Actual values vary with brands, substitutions, cooking losses, oil absorption, and portion size.

Ingredients

Have these measured and ready before you begin.

  • 2 medium onions
  • 3–4 tbsp neutral oil
  • 1 tbsp butter
  • 3 tbsp all-purpose flour
  • 1 tsp ground black pepper
  • 1 tsp fine salt
  • 5 7/8 cups (1.4 liters) water
  • scant 1/2 cup (100 ml) milk

Directions

1. Slice the onions into thin strips. Heat the neutral oil in a pot and cook the onions slowly until deeply softened and caramelized.

2. Add the butter. When melted, stir in the flour and cook until it smells toasted but does not burn.

3. Gradually whisk in the water, then add the salt and black pepper. Bring to a boil.

4. Stir in the milk and simmer for 10 minutes.

5. Blend until smooth, taking care with the hot liquid, and serve.

Sources

  1. USDA FoodData Central — April 2026 data release

Contains milk and wheat. Vent a countertop blender and work in batches with hot soup; refrigerate leftovers within 2 hours.

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