Some soups are fancy. This one is a warm blanket. My Potato & Leek Soup with Dill takes a humble pile of leeks, onion, celery and Yukon gold potatoes and blends them into something so silky you will swear there is a carton of cream hiding in it. There isn’t. The secret is buttermilk, which gives this potato leek soup a gentle tang and a velvety finish, while a handful of fresh dill stirred in at the end keeps it bright instead of heavy.

It is the kind of soup I make on a grey Sunday and then happily eat for lunch all week. The ingredients are cheap and cheerful, the method is mostly hands-off, and the only slightly tricky bit (blending hot soup without redecorating your kitchen) is covered step by step below.

Why You’ll Love This Potato & Leek Soup with Dill

• Creamy without the cream. Blended Yukon golds do all the thickening, and buttermilk adds richness and tang without weighing the soup down.
• Fresh dill makes it sing. A quarter cup of chopped dill brightens every spoonful and gives a classic soup a little something extra.
• Budget friendly. Leeks, potatoes, onion and celery are about as affordable as it gets, especially in the cooler months.
• Mostly hands-off. Once the vegetables are softened, the pot simmers on its own while you get on with your day.
• Lunch for days. It reheats beautifully, so one pot takes care of several lunches.

Ingredients

• 1 tbsp vegetable oil
• 1 tbsp butter
• 2 leeks, sliced into half moons
• 1 cooking onion, diced
• 2 stalks of celery, sliced
• 3 Yukon gold potatoes, peeled and diced
• 4 cups chicken stock
• 3 sprigs fresh thyme
• 2 cups buttermilk
• ¼ cup chopped dill

Tips for the Best Potato Leek Soup

• Wash your leeks well. Leeks love to hide grit between their layers. Slice them first, then swish the half moons in a big bowl of cold water and lift them out, leaving the sand behind.
• Go low and slow on the veg. You want the leeks, onion and celery soft and translucent, not browned. Browning adds a toasty flavour that muddies the fresh, clean taste of the soup.
• Stick with Yukon golds. They are naturally buttery and blend up silky smooth. Starchy russets can turn gluey in the blender.
• Respect the steam. Hot soup in a sealed blender can blow the lid right off. Blend in batches, vent the cap and cover it loosely with a towel, exactly as in the method.
• Never boil after the buttermilk. Once the buttermilk goes in, keep the heat very low. A boil can make it curdle, and grainy soup is nobody’s favourite.
• Season to taste. Stocks vary a lot in saltiness, so give the finished soup a taste and add salt and pepper as needed.

How to Make Potato & Leek Soup with Dill

1. Place a large pot over medium heat and add the canola oil and butter. Once the butter is melted, stir in the leeks, onion and celery. Turn the heat to medium low and cook for 10 min until the vegetables are soft and translucent.
2. Add the potatoes, chicken stock and fresh thyme sprigs. The stock should just cover the vegetables by about 1-inch, add more stock as needed. Cover the soup and bring to a simmer, cook for 15-20 minutes or until the potatoes are tender.
3. Remove the thyme sprigs. Carefully transfer the contents of the soup pot to a blender (or use an immersion blender). If the blender is small, blend the soup in two batches. Untwist the funnel cap from the top of the blender to allow the steam to escape, but don’t take it off. Use a kitchen towel to loosely cover the cap. Blend until the soup is thick and creamy.
4. Return the blended soup to the pot and stir in the buttermilk and dill. Heat over a very low burner. Don’t bring the soup to a boil again as the buttermilk might curdle. Serve.

Storage: Keep leftovers in an airtight container in the fridge for up to 3 days. Reheat gently over low heat, stirring often, and don’t let it boil. If you want to freeze a batch, freeze the blended soup before adding the buttermilk and dill, then stir those in when you reheat.

More Cozy Soups and Leek Recipes to Try

If a bowl of this has you in full soup season mode, try these next:

• Corn Chowder with Leeks and Bacon: a hearty, smoky chowder for when you want more leeks in your life
• Creamy Celery and Potato Soup with Chorizo: another silky potato soup, with a spicy chorizo topping
• Easy Vegetable Chowder: a chunky, veggie-loaded bowl that is easy on the budget
• Leek and Potato Pie: the same classic combo, baked into a cozy pie
• Crock Pot French Onion Soup: a hands-off slow cooker soup for busy days

External Resources

• FoodSafety.gov FoodKeeper App: how long soups and dairy like buttermilk stay safe in the fridge and freezer
• Dairy Farmers of Canada: background on Canadian dairy, including buttermilk

Frequently Asked Questions

Can I use regular milk instead of buttermilk in potato leek soup? You can, but you will lose the tang that makes this version special. If you only have milk, stir in a squeeze of lemon juice at the end to bring back a little brightness.

Why did my potato leek soup with buttermilk curdle? It almost always means the soup got too hot after the buttermilk went in. Keep the burner very low and warm it gently, and never let it come back to a boil.

Can I freeze potato leek soup? Yes, with one trick: freeze it after blending but before adding the buttermilk and dill. Thaw, reheat gently, then stir in the buttermilk and dill.

How do I clean leeks? Trim off the root and the dark green tops, slice the leeks into half moons, then swish them in a big bowl of cold water. The grit sinks to the bottom and you lift the clean leeks out.

What are the best potatoes for this soup? Yukon golds. They are creamy and buttery and blend up silky, while starchy russets can turn gluey when blended.

Can I make this soup vegetarian? Absolutely. Swap the chicken stock for vegetable stock and you are all set.

Can I use dried dill instead of fresh? Fresh is best here since it is a star of the show, but in a pinch use about a tablespoon of dried dill and add it with the buttermilk.

Potato & Leek Soup with Dill

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A silky potato leek soup made creamy with buttermilk instead of cream and finished with plenty of fresh dill.

• Author: Andrea Buckett
• Prep Time: 15 minutes
• Cook Time: 40 minutes
• Total Time: 55 minutes
• Yield: 6 servings

Ingredients

Units USM

• 1 tbsp vegetable oil
• 1 tbsp butter
• 2 leeks, sliced into half moons
• 1 cooking onion, diced
• 2 stalks of celery, sliced
• 3 Yukon gold potatoes, peeled and diced
• 4 cups chicken stock
• 3 sprigs fresh thyme
• 2 cups buttermilk
• 1/4 cup chopped dill

Instructions

1. Place a large pot over medium heat and add the canola oil and butter. Once the butter is melted, stir in the leeks, onion and celery. Turn the heat to medium low and cook for 10 min until the vegetables are soft and translucent.
2. Add the potatoes, chicken stock and fresh thyme sprigs. The stock should just cover the vegetables by about 1-inch, add more stock as needed. Cover the soup and bring to a simmer, cook for 15-20 minutes or until the potatoes are tender.
3. Remove the thyme sprigs. Carefully transfer the contents of the soup pot to a blender (or use an immersion blender). If the blender is small, blend the soup in two batches. Untwist the funnel cap from the top of the blender to allow the steam to escape, but don’t take it off. Use a kitchen towel to loosely cover the cap. Blend until the soup is thick and creamy.
4. Return the blended soup to the pot and stir in the buttermilk and dill. Heat over a very low burner. Don’t bring the soup to a boil again as the buttermilk might curdle. Serve.

Notes

• Leeks. Rinse the sliced leeks well in a bowl of cold water to remove any grit.
• Buttermilk. Keep the heat very low once the buttermilk is added. Boiling can cause it to curdle.
• Seasoning. Taste the finished soup and season with salt and pepper as needed.
• Storage. Refrigerate leftovers for up to 3 days and reheat gently without boiling. To freeze, freeze the blended soup before adding the buttermilk and dill, then stir them in when reheating.