Equipment
Ingredients
Aromatics and Fat
- 30 ml olive oil, extra virgin
- 1 yellow onion, chopped
- 1 leek, white and light green parts only, sliced and washed
- 2 garlic, minced
Main Vegetables and Fruit
- 500 g celeriac, peeled and cut into 2cm cubes
- 300 g yukon gold potatoes, peeled and cut into 2cm cubes
- 300 g granny smith apples, peeled, cored, and chopped
Liquids and Seasonings
- 1000 ml vegetable broth, low sodium preferred
- 2 fresh thyme, whole sprigs
- 5 g kosher salt, plus extra to taste
- 2 g black pepper, freshly ground
- 1 g ground nutmeg
Garnish
- 5 g fresh chives, finely chopped
Nutrition (per serving)
Nutrition is estimated per serving. Nutrients without complete source data are omitted.
Full nutrition
- Calories
- 482 kcal
- Protein
- 9 g
- Carbohydrates
- 95 g
- Fat
- 9 g
- Fiber
- 10 g
- Sugar
- 16 g
- Sodium
- 1417 mg
- Saturated Fat
- 1 g
- Monounsaturated Fat
- 6 g
- Polyunsaturated Fat
- 1 g
- Potassium
- 1389 mg
- Calcium
- 148 mg
- Iron
- 3.1 mg
- Magnesium
- 94 mg
- Phosphorus
- 312 mg
- Zinc
- 1.1 mg
- Vitamin A
- 69 mcg
- Vitamin C
- 22 mg
- Vitamin E
- 2.1 mg
- Vitamin K
- 71 mcg
- Vitamin B6
- 1.0 mg
- Thiamin
- 0.34 mg
- Riboflavin
- 0.19 mg
- Niacin
- 4.1 mg
- Folate
- 55 mcg
- Water
- 480 g
Sources: Aggregated Public Data, USDA FoodData Central
Method
Heat the olive oil in a large pot or Dutch oven over medium heat. Add the chopped onion, sliced leek, and minced garlic. Stir frequently and sweat the aromatics for 5 to 7 minutes until they are completely softened and translucent, ensuring they do not brown.
Add the cubed celeriac, potatoes, and apples to the pot. Stir well to coat the ingredients with the oil and aromatics. Cook for 3 minutes to lightly toast the exterior of the vegetables and begin releasing their flavors.
Pour in the vegetable broth, then add the fresh thyme sprigs, salt, and black pepper. Bring the liquid to a rolling boil at 100°C/212°F.
Reduce the heat to medium-low to maintain a gentle simmer at approximately 90°C/195°F. Cover the pot with a lid and simmer for 20 to 25 minutes. The soup is ready for blending when a knife easily pierces the largest pieces of celeriac and potato with zero resistance.
Remove the pot from the heat. Carefully fish out and discard the thyme sprigs. Using an immersion blender, puree the soup directly in the pot until perfectly smooth and velvety. If using a standard countertop blender, allow the soup to cool slightly, work in batches, and never fill the blender pitcher more than halfway to prevent hot explosions.
Stir in the ground nutmeg. Taste the soup and adjust the seasoning with additional salt or pepper if needed. Ladle into warm bowls and garnish with finely chopped fresh chives and a few drops of olive oil.
Chef's Notes
- Celeriac has a thick, knobby exterior that traps dirt. Be aggressive when peeling it; you want to remove all the fibrous, brown roots to expose only the clean, white flesh.
- The choice of apple heavily influences the final flavor. A tart variety like Granny Smith prevents the soup from becoming cloyingly sweet and balances the starchiness of the potatoes.
- If you are not strictly dairy-free or vegan, replacing the olive oil finish with a swirl of heavy cream or creme fraiche will elevate the mouthfeel even further.
- Always wash leeks thoroughly after slicing. They are grown in sandy soil and dirt tends to hide tightly between their layers.
Storage
Refrigerator: 4 days — Store in an airtight container. The soup may thicken when chilled; add a splash of water or broth when reheating.
Freezer: 3 months — Freeze in individual portions leaving room for expansion.
Reheating: Warm gently in a saucepan over medium-low heat, stirring frequently until heated through.
Troubleshooting
Soup texture is grainy or slightly lumpy
Cause: The celeriac was not cooked thoroughly before blending, or the blender power was insufficient
Fix: Return the soup to a simmer for 10 more minutes, then blend again thoroughly
Prevention: Ensure all vegetables are completely tender before attempting to puree
Soup is too thick
Cause: High evaporation during simmering or highly starchy potatoes absorbed too much liquid
Fix: Whisk in hot water or warm vegetable broth 50ml at a time until the desired velvety consistency is reached
Prevention: Keep the pot fully covered while simmering and maintain a gentle heat
Flavor feels flat or overly earthy
Cause: Under-seasoning or lack of acidity
Fix: Add a pinch of salt and half a teaspoon of apple cider vinegar or lemon juice to brighten the flavor profile
Prevention: Taste and season iteratively during the final steps
Cultural Context
Rooted in classic French culinary traditions, pureed vegetable soups, or potages, were historically a frugal yet elegant way to use abundant winter cellar vegetables. The addition of apple represents a modern culinary approach, utilizing natural orchard fruit sweetness to tame the strong, earthy aroma of root vegetables, making it a perfect staple for the harvest season.
