Finnish Summer Vegetable Soup with New Potatoes

Finnish summer vegetable soup, or kesäkeitto, is a gentle milk-based soup of tender new potatoes and seasonal vegetables, finished with dill. The vegetables keep their distinct textures while a lightly thickened, buttery broth brings them together, making this a simple meal for a cool summer evening or a light lunch.

Ingredients

1 lb small new potatoes (450 g), scrubbed; halve or quarter larger ones
2 medium carrots (about 6 oz / 170 g), peeled and cut into ½-inch (1 cm) pieces
1 small cauliflower (about 12 oz / 340 g whole), cut into bite-size florets
1 cup trimmed green beans (120 g), cut into 1-inch (2.5 cm) lengths
1½ cups shelled fresh peas (200 g), or frozen peas, thawed
4 cups water (950 ml)
1 teaspoon fine salt (6 g), plus more to taste
2 tablespoons unsalted butter (28 g)
2 tablespoons all-purpose flour (16 g)
3 cups whole milk (710 ml)
½ cup heavy cream (120 ml)
¼ teaspoon ground white pepper (about 0.5 g), or black pepper to taste
¼ cup chopped fresh dill (about 10 g), plus a little more for serving

Instructions

Prepare the vegetables. Scrub the potatoes and cut any larger ones so the pieces are roughly even. Prepare the carrots, cauliflower, green beans, and peas. Keeping the pieces similar in size helps them cook evenly, while adding the vegetables in stages prevents the softer ones from turning mushy.
Start the potatoes and carrots. Put the potatoes, carrots, water, and 1 teaspoon salt in a large, heavy-bottomed pot. Bring to a boil over medium-high heat, which usually takes about 6 minutes. Lower the heat to maintain a gentle simmer and cook for 9 minutes, or until the potatoes are just beginning to yield when pierced with a knife. Avoid a hard boil; it can break up the potatoes and make the broth cloudy.
Add the cauliflower and beans. Stir in the cauliflower florets and green beans. Simmer gently for 5 minutes. Check a piece of each: the vegetables should be tender-crisp, not soft enough to collapse. If your cauliflower pieces are especially small, begin checking after 4 minutes.
Add the peas. Stir in the fresh or thawed peas and simmer for 2 minutes. If using frozen peas straight from the freezer, give them an extra minute if needed. Take the pot off the heat while you prepare the milk mixture, so the vegetables do not overcook.
Make a smooth thickener. In a small saucepan, melt the butter over medium-low heat. Whisk in the flour and cook for 2 minutes, whisking steadily. The mixture should look smooth and pale, without browning. Slowly pour in the milk while whisking to prevent lumps. Add the cream and white pepper, then warm the mixture for about 5 minutes, stirring often, until steaming and slightly thickened. Do not let it boil vigorously.
Finish the soup. Pour the warm milk mixture into the pot of vegetables and return the pot to low heat. Stir gently and warm for about 1 minute, just until everything is hot and the broth has an even, lightly creamy texture. Do not bring it to a rolling boil after adding the dairy, which can cause a grainy look or a skin to form.
Season and serve. Stir in the chopped dill. Taste the broth and add salt or pepper a little at a time. Ladle into warm bowls and finish with extra dill. The vegetables should be distinct and tender, surrounded by a mild broth rather than a thick, heavy sauce.

Tips

Choose vegetables by size and firmness. Small new potatoes are especially convenient because their thin skins do not need peeling. If using larger potatoes, cut them into even bite-size pieces. Very starchy potatoes can shed more into the broth, so waxy or all-purpose varieties are a dependable choice.
Keep the simmer gentle. Once the vegetables are in the pot, small bubbles are enough. A vigorous boil can split potatoes, break up cauliflower, and make the finished soup less clear. Stir carefully with a broad spoon instead of beating the vegetables around.
Use a whisk for the milk mixture. Adding cold milk directly to a flour-and-butter mixture all at once can create lumps. Whisk in the milk gradually, and keep the mixture below a hard boil. If a few small lumps remain, whisk the sauce before combining it with the vegetables.
Adjust the richness, not the cooking method. Whole milk and cream make a rounded broth, but you can use 3 cups (710 ml) whole milk without cream for a lighter result. The soup will be less rich. Lower-fat milk also works, though the broth will be thinner and may need a little extra flour mixture if you prefer a more coating texture.

Serving Suggestions

Serve the soup hot in bowls, with the dill visible on top and a little black pepper if desired. Rye bread, sourdough, or a crusty wheat roll is useful for catching the creamy broth; buttered bread is a particularly simple accompaniment. For a fuller lunch, add a small green salad with a sharp vinaigrette on the side. Its acidity contrasts nicely with the mild milk broth without competing with the fresh vegetables.

This soup can also be served as a first course before grilled fish, roast chicken, or a savory pie. Keep portions modest if it is part of a larger meal, since the potatoes make it more substantial than a clear vegetable broth. If serving several people, warm the bowls with hot water and dry them before ladling; the soup stays more pleasant at the table when it does not cool immediately.

Variations

Follow the market vegetables. Kesäkeitto is associated with Finnish summer cooking, but household versions vary with what is available. Replace the green beans with 1 cup (120 g) sliced tender zucchini, adding it with the cauliflower. Small turnips or young kohlrabi can stand in for some of the carrots; peel them and cut them into small pieces so they become tender in the same window. The flavor will shift slightly, but the basic milk-and-dill character remains.

Use frozen vegetables when fresh ones are out of season. Frozen peas work very well and need only a short simmer. Frozen green beans can be used too, but add them according to the package size and check for tenderness early. Avoid adding a large block of frozen vegetables at once, because it can stop the simmer and lengthen the cooking time unevenly.

Make it dairy-free. Use a neutral plant-based butter and unsweetened, unflavored oat milk or soy milk in place of the dairy. Choose a product intended for cooking, since some plant milks taste sweet or separate when heated. The result will not have the same traditional buttery dairy flavor, but dill and freshly ground pepper help keep it savory. A tablespoon of flour whisked into the melted plant butter provides the same gentle thickening.

Change the herbs or richness. Fresh chives can replace some of the dill, though dill is the characteristic finish. For a richer bowl, increase the cream to ¾ cup (180 ml) and reduce the milk by ¼ cup (60 ml). For a thinner soup, omit the flour and butter mixture and simply warm the milk and cream before stirring them in; the broth will be more fluid and less velvety.

Storage and Reheating

Cool leftovers promptly and refrigerate them within 2 hours of cooking, in a covered shallow container. The soup keeps for 3–4 days in the refrigerator. Because potatoes and vegetables continue to soften as they sit, the texture is best on the first day, but careful reheating helps preserve it. If the broth thickens in the fridge, stir in a splash of milk or water before warming.

Reheat only the portion you plan to eat in a saucepan over low to medium-low heat, stirring gently until it is steaming throughout and reaches 165°F (74°C), the USDA FSIS temperature for reheated leftovers. Avoid boiling it, which can make the dairy look separated and further soften the vegetables. A microwave also works: cover loosely, heat in short intervals, and stir between intervals so the center warms evenly. Do not repeatedly cool and reheat the full pot.

Freezing is possible, but it is not ideal for this soup. Milk-based broth may separate after thawing, and potatoes can turn grainy or mealy. If you need to freeze it, expect a change in texture; thaw overnight in the refrigerator and reheat gently while stirring. For a better result, freeze the cooked vegetables and broth before adding the dairy thickener, then prepare and stir in fresh milk mixture after thawing and reheating.

Frequently Asked Questions

What does kesäkeitto mean?
Kesäkeitto is Finnish for “summer soup.” It commonly refers to a mild soup made with seasonal vegetables and a milk-based broth. There are family and regional variations, so the precise vegetable selection and degree of richness are not fixed.

Do I have to peel new potatoes?
No. The thin skins of small new potatoes are usually left on; scrub them well and remove any damaged spots. If the potatoes are older or have thick, tough skins, peel them for a softer, more even texture. Cutting them to a similar size matters more than whether they are peeled.

Can I make this soup without flour?
Yes. Leave out the butter and flour and warm the milk and cream gently before adding them to the vegetables. The broth will be thinner, closer to a light milk soup. For a gluten-free thickened version, use a certified gluten-free all-purpose flour blend in the same quantity, or whisk 1 tablespoon (8 g) cornstarch with a little cold milk and stir it into the warm soup; heat gently until slightly thickened.

Can I prepare Finnish summer vegetable soup ahead?
You can cut the vegetables a few hours in advance and keep them covered in the refrigerator. For the best texture, cook the soup shortly before serving, because the vegetables soften as they stand in hot broth. If you make the full soup ahead, cool and refrigerate it promptly, then reheat gently to 165°F (74°C) and add a little milk if the broth has thickened.

Why did my milk broth separate?
A hard boil after adding milk or cream is the most common reason for a grainy or separated appearance. Heat the dairy mixture until steaming, combine it with the vegetables over low heat, and avoid boiling the finished soup. It is still generally usable if it separates, though the texture may be less smooth; stir gently and serve rather than trying to boil it back together.

Can I use dried dill instead of fresh?
Yes, though its flavor is less bright. Start with 1 teaspoon dried dill (about 1 g) in place of the ¼ cup fresh dill, then taste and add a little more if you like. Stir dried dill in with the warm milk mixture so it has a few minutes to release its flavor, and finish with fresh chopped chives or parsley if available.

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Safety notes: safe minimum internal temperatures from USDA FSIS; raw and undercooked fish guidance from the U.S. FDA. Food safety notes

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