FrenchMedium · Hot
French Leek and Potato Soup with Thyme Butter
A classic French bistro-style vichyssoise-inspired soup combining tender leeks and potatoes finished with fragrant thyme butter. Rich, herbal, and deeply satisfying.
Prep
15 min
Cook
30 min
Total
45 min
Method
Preparation
1
Trim the dark green tops from the leeks and slice the white and light green parts into half-moons. Submerge the sliced leeks in cold water, swish gently to release any trapped sand, then lift out and drain well.
2
Peel the potatoes and cut into 1-inch cubes. Dice the yellow onion. Mince the garlic cloves.
3
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Thyme Butter
4
While the soup simmers, combine the remaining 2 tablespoons of butter with the fresh thyme sprigs in a small saucepan over low heat. Let the butter melt slowly and infuse with thyme for 5 minutes, then remove from heat and set aside.
Blending and Finishing
5
Using an immersion blender or careful transfer to a standing blender, puree the soup until completely smooth and velvety.
6
Return the pureed soup to the saucepan over medium-low heat. Stir in the heavy cream and white pepper. Taste and adjust seasoning with additional salt if needed.
A
Nutri-Score
Excellent balance
A–E · lower is better · score -2
Calories
272
per serving
Low sugar · 6g
Protein
4g
Carbs
32g
Fat
15g
Sat. fat
8g
Fiber
4g
Sugar
6g
Sodium
622mg
Gluten FreeLacto Vegetarian AdaptableHeart Healthy AdaptableLow Sodium AdaptableDiabetes FriendlyBalanced MacroFiber BoostComfort Food
Nutri-Score is a general nutritional-balance guide, not medical or dietary advice.
A
Environmental impact
Very low impact
A–E · lower is better · includes estimates
kg CO2e
0.3
per serving
ACarbonAEU all-round· both agree
Water
0.1m³
Land
13Pt
Runoff
0.04g P
Unsalted Butter drives 31% of this recipe’s estimated footprint.
Carbon from Poore & Nemecek 2018; water, land & runoff from Agribalyse — modelled averages for comparing recipes, not a measurement of your groceries.
Flavor Profile
7
Umami
5
Sweet
5
Salty
2
Sour
1
Bitter
2
Spicy
Textures
SilkyVelvetyTenderCreamy
Aromas
HerbalButteryAlliumSavory
Kitchen Equipment
Primary Tool
Large SaucepanCounter FootprintMedium
Safety & Storage
Cross Contamination
Chicken broth may contain gluten depending on the brand. Verify that broth is gluten-free if serving to individuals with celiac disease or gluten sensitivity. Use dedicated utensils and clean equipment thoroughly between uses.
Equipment Safety
When pureeing hot liquids in a blender, never fill the container more than half full. Allow soup to cool slightly before blending, or use an immersion blender directly in the pot to avoid pressure buildup and potential burns from hot liquid expansion.
Cooking Temperature
Ensure soup reaches a rolling simmer (185°F/85°C) for at least 15 minutes when cooking potatoes to ensure they are fully tender and safe to consume. Butter should melt over low heat without smoking.
Storage
Refrigerate soup within 2 hours of cooking. Store in airtight containers and consume within 3-4 days. The dairy content makes this soup perishable. Reheat to 165°F (74°C) before serving leftover portions.
High Risk Population
This recipe contains dairy (milk allergen). Individuals with lactose intolerance, milk allergy, or dairy-free dietary requirements should avoid this dish. Heavy cream and butter are core ingredients that cannot be easily substituted without significantly altering the recipe.
Pro Tips
Technique
When cleaning your leeks, do not rush this step. Sand has a way of hiding in the layers, and there is nothing more disappointing than a silky soup with that telltale grit. Submerge, swish, lift, and repeat until the water runs clear.
Substitution
If you wish to deepen the allium character, replace half the yellow onion with a shallot or two. I would never tell you this in the kitchen itself, but your guests will notice and ask questions you will be proud to answer.
From the chef
In Lyon, we called this potage when the weather turned and the bistro windows fogged with steam. A good leek and potato soup is deceptively simple, but like all French classics, the magic lies in technique—building fond, coaxing sweetness from the vegetables, and finishing with butter that carries the thyme like a love letter. I have served this to critics and to children, and I assure you, the children leave more satisfied.
TagsFrenchComfort FoodDairyHerbsPureedLeekPotato
AllergensMilk
Source: generated · June 10, 2026