Potato Leek Soup
Recipe by Steven Weitzman, founder & head chef of Grilly CheesePublished 2026-10-27Updated 2026-10-27
Potato leek soup with tender potatoes, softened leeks, and milk. A lightly chunky skillet soup with about 30 minutes of active work for grilled cheese night.
Potato leek soup is a comforting blend of tender potatoes, softened leeks, and broth that makes a mild, creamy side for a crisp grilled cheese sandwich. This skillet version stays lightly chunky. A potato masher thickens the broth while leaving small potato pieces and soft leeks, and a little whole milk rounds out the finish. There is no blender step. Makes: about 5 cups, or 4 side servings. Prep: 15 minutes. Cook: about 40 minutes. Total: 55 minutes, with about 30 minutes of active work. Most of the remaining time is a covered simmer.
How to make Potato Leek Soup
Makes About 5 cups; 4 side-dish servings. Listed times are estimates; visual and temperature cues control doneness.
15 minCook
40 minRest
0 minTotal
55 minYield
About 5 cups; 4 side-dish servings
Equipment
- Cutting board and sharp knife
- Vegetable peeler
- Large bowl for washing leeks
- Strainer
- Measuring cups and spoons
- Deep 4-quart saute skillet with lid
- Wooden spoon
- Potato masher
- Ladle
- Trivet
Ingredients
- •2 medium leeks, white and light-green parts only, thinly sliced, about 2 cups (200 g) after trimming: Use the trimmed weight or volume, since leek sizes vary.
- •2 tablespoons unsalted butter
- •1 pound (450 g) peeled russet potatoes, cut into 1/2-inch cubes: Weight is after peeling. Buy about 1 1/4 pounds to allow for trimming.
- •3 cups (720 ml) low-sodium vegetable broth
- •1/4 teaspoon dried thyme
- •1/2 teaspoon fine salt
- •1/8 teaspoon ground black pepper
- •1/2 cup (120 ml) whole milk
Instructions
- 1
Clean and soften the leeks
Put the sliced leeks in a bowl of cold water and swish well to loosen grit. Lift them out, leaving sediment behind, and drain in a strainer; repeat with fresh water if needed. Melt the butter in a deep 4-quart saute skillet over medium-low heat. Add the drained leeks and cook for 7–8 minutes, stirring, until soft and translucent without browning.
- 2
Simmer the potatoes
Add the potatoes, vegetable broth, thyme, salt, and pepper. Bring to a gentle boil over medium heat, then reduce the heat, cover, and simmer for 18–22 minutes, stirring once or twice, until a potato cube crushes easily with a spoon. Keep the simmer gentle and continue a little longer if the potatoes are still firm.
- 3
Mash and finish with milk
Remove the skillet from the heat and set it on a trivet. Mash some of the potatoes gently with a potato masher, leaving small pieces and leek strands for texture. Stir in the milk, return to low heat, and warm for 2–3 minutes, stirring, until hot without a vigorous boil. Serve hot. Allow about 40 minutes for cooking and finishing.
Tips
- →Trim away dark-green tough leaves and the root end before slicing the leeks.
- →Lift the washed leeks out of the water rather than pouring gritty water back through them.
- →Cut the potatoes into even 1/2-inch cubes so tenderness is consistent.
- →Test a potato before mashing; it should crush easily.
- →Mash gently and stop when the broth thickens enough for your preference.
- →Stir along the bottom as the finished soup warms, since thick potato soup can catch.
- →Taste before adding extra salt, especially if using regular broth.
Variation
Yukon Gold potatoes: Use the same peeled weight. They hold their shape more firmly and give a slightly different texture, so mash a little more if needed. Chicken broth: Substitute in the same volume if a vegetarian soup is not required. Dairy-free version: Use 2 tablespoons olive oil instead of butter and 1/2 cup plain unsweetened oat milk instead of dairy milk. Check the broth for your dietary needs. Consistency: If the soup is too thick after mashing, add warm broth or milk 1 tablespoon at a time. If too thin, mash a few more potato pieces or simmer gently uncovered while stirring. Adjustments change the yield slightly.
Questions and answers
What part of the leek do you use for potato leek soup?
Use the white and light-green parts for this recipe. Remove the root end and tough dark-green leaves, then wash the sliced leeks thoroughly.
How do you clean leeks for soup?
Slice them, swish in a bowl of cold water, and lift them out so grit stays at the bottom. Repeat with fresh water if needed, then drain before cooking.
What potatoes are best for potato leek soup?
Russets soften readily and mash into the broth for a thick, lightly chunky soup. Yukon Gold potatoes also work but hold their shape more firmly.
Can you make potato leek soup without cream?
Yes. This recipe uses milk, and mashed potatoes provide most of its body. No heavy cream or flour is needed.
Do you have to blend potato leek soup?
No. A potato masher thickens this version while leaving small potato pieces and soft leek strands. Stop mashing when you like the texture.
Why is my potato leek soup too thick?
The potatoes release starch, and the soup thickens more as it stands or chills. Stir in a little warm broth or milk to loosen it before serving.
Storage and reheating
Grilled cheese is best eaten right away. Refrigerate leftovers promptly in a covered, shallow container at 40°F (4°C) or below, within 2 hours of cooking—or within 1 hour when the temperature is above 90°F (32°C). Use within 3–4 days. Reheat to 165°F (74°C), checking the center with a food thermometer. A skillet over low heat, briefly covered and then uncovered, can warm the center and help restore the crust. If using previously cooked chicken or other leftovers, count storage time from when that ingredient was first cooked. See USDA leftovers guidance and FoodSafety.gov minimum temperatures.
Dietary note: This recipe is labeled VegetarianDiet.
Did you make it?
Rate this recipe to help other cooks.
More grilled cheese recipes
Planning an event? Explore hiring a Grilly Cheese food truck.