Finnish Spinach Soup: Creamy, Simple, and Comforting

Finnish spinach soup, or pinaattikeitto, is a gently seasoned, milk-based soup made with spinach and a simple butter-and-flour thickener. It is often served with hard-boiled eggs, which add a satisfying contrast to the smooth soup; home-style versions vary in thickness and seasoning.

Ingredients

10 oz (283 g) frozen chopped spinach, thawed and squeezed dry
4 tbsp (57 g) unsalted butter
1/4 cup (32 g) all-purpose flour
4 cups (960 ml) whole milk
1 cup (240 ml) water
3/4 tsp (4.5 g) fine salt, plus more to taste
1/8 tsp (0.3 g) ground white or black pepper
1/8 tsp (0.3 g) freshly grated nutmeg, or a small pinch of ground nutmeg
1 tsp (4 g) granulated sugar, optional, to round out the spinach’s earthy flavor
4 large eggs, for serving

Instructions

Thaw and prepare the spinach. If the spinach is not already thawed, microwave it according to the package directions or use the defrost setting, then let it cool enough to handle. Squeeze it firmly over the sink in a clean towel or with your hands until it is no longer dripping. This keeps excess water from thinning the soup. Break up any dense clumps with a fork. Set out the measured milk and water as well; having them ready makes it easier to whisk a smooth base.
Start the eggs. Put the eggs in a small saucepan and cover them with cold water by about 1 inch (2.5 cm). Bring the water to a boil over medium-high heat. Once it boils, cover the pan, take it off the heat, and let the eggs stand for 10 to 12 minutes. Transfer them to a bowl of cold or iced water for about 5 minutes, then peel and halve them. Cook whole eggs until the yolks and whites are firm. The egg cooking and cooling can happen while you make the soup.
Make the roux. Melt the butter in a medium heavy-bottomed saucepan over medium-low heat. Sprinkle in the flour and whisk steadily for 1 to 2 minutes, until the mixture is smooth and smells lightly buttery rather than raw. Keep it pale; browning the flour gives the soup a toasted flavor and a darker color that are not the aim here. If flour sticks in the corners, scrape the bottom and sides of the pan with a heatproof spatula.
Whisk in the liquid gradually. Pour in about 1/2 cup (120 ml) of the milk while whisking to make a thick, smooth paste. Add the remaining milk in several pours, whisking well after each addition, then whisk in the water. This gradual start helps prevent flour lumps. Raise the heat to medium and continue stirring as the mixture warms. It should become lightly thickened and show small bubbles around the edge; avoid letting it boil hard, which can cause milk to scorch or foam over.
Simmer with the spinach. Stir in the squeezed spinach, salt, pepper, nutmeg, and optional sugar. Reduce the heat to low and cook gently for 8 to 10 minutes, stirring often and scraping the bottom so the milk does not catch. The finished soup should coat a spoon but still pour easily. Taste it and adjust the salt, pepper, or nutmeg a little at a time. If it seems thicker than you like, stir in a splash of milk or water; if it is too loose, simmer it gently for another minute or two while stirring.
Serve warm. Ladle the soup into bowls and top each serving with a halved hard-boiled egg. Give the soup a final stir before serving so the spinach is evenly distributed. The soup is best served hot but not scalding, with extra pepper at the table if desired.

Tips

Squeeze thawed spinach well. Frozen spinach holds more water than it appears to, and that liquid can make a carefully thickened soup watery. Squeeze it in batches if needed. If you are using a package that contains unusually large pieces, chop them after squeezing so they are easy to spoon up.
Keep the roux pale and whisk patiently. A low-to-medium-low heat gives you time to combine the butter and flour without browning them. Adding milk gradually at first is more reliable than pouring it all in at once. If a few small lumps remain, whisk vigorously; for a completely smooth texture, briefly blend the milk base before adding the spinach.
Adjust thickness with small additions. Different spinach brands release different amounts of water, and flour can measure differently when packed. The soup thickens a little as it stands, so start with the quantities listed and add milk or water by the tablespoon if needed. Avoid correcting a thin soup with a large scoop of flour, which can leave a raw, pasty taste.
Choose fresh spinach only if you account for its volume. For a fresh-spinach version, use about 1 lb (450 g) trimmed leaves, wilt them in a covered pan with a splash of water, cool, chop, and squeeze out excess liquid. Fresh leaves cook down dramatically and can taste slightly brighter; frozen chopped spinach is more convenient and gives the soup its familiar soft, even texture.

Serving Suggestions

Serve the soup as a light lunch or as a first course, with one egg half or a whole halved egg per bowl. Rye bread is a natural partner: its tangy, hearty flavor works well with the mild milk base. A slice of Finnish-style dark rye, crispbread, or a simple buttered roll is useful for dipping. For a fuller meal, add boiled potatoes on the side or serve a modest sandwich alongside rather than loading the soup with extra ingredients.

Keep accompaniments fairly simple so the spinach and nutmeg remain noticeable. A small pat of butter on warm bread, a little extra black pepper, or a pinch of chopped dill at the table can be enough. If serving several people, ladle the soup first and add the egg halves individually; that makes it easier to give everyone the same amount and keeps the eggs from breaking up in the pot.

Variations

Use a different milk. Whole milk gives the soup its rounded, creamy texture. Reduced-fat milk works, though the result is a little lighter. Unsweetened oat milk can be used for a dairy-free version, but choose one with a neutral flavor and no added sugar; it may make the soup taste slightly sweeter or less traditionally milky. Replace the butter with a neutral plant-based butter and check that it is suitable for cooking. Avoid strongly flavored milks, which can compete with the spinach.

Make it thicker or thinner. For a spoon-coating, extra-comforting bowl, use 3 1/2 cups (840 ml) milk and keep the other quantities the same. For a thinner soup, add up to another 1/2 cup (120 ml) milk or water near the end, tasting again for salt. The flour-and-butter base is the classic way to thicken this style of soup; simply blending in more spinach will make it greener and more vegetable-forward, but will not have the same smooth, creamy consistency.

Change the seasoning gently. A small pinch of white pepper gives a delicate finish, while black pepper is easy to use and slightly more assertive. Nutmeg is traditional in many milk-based spinach soups, but it should not dominate; leave it out if you do not enjoy it. A teaspoon of sugar is optional rather than essential. Some cooks prefer a very plain seasoning, while others add a touch more salt or pepper at the table.

Make it without the egg garnish. The hard-boiled egg is a familiar serving addition, not something that needs to be stirred into the soup. Leave it off for a simpler bowl, or offer it separately so diners can choose. The soup itself contains no meat or stock in this recipe, so there is no need to replace the egg with another ingredient for the soup to work. A side of bread or potatoes can make the meal more substantial.

Storage and Reheating

Cool leftover soup promptly and refrigerate it within 2 hours of cooking in a covered, shallow container. Keep the eggs separate if possible, since peeled eggs can become rubbery when reheated in the soup. Refrigerated soup keeps for 3 to 4 days. Store the eggs in a separate covered container and use them within the same general leftover window; discard anything that has been left at room temperature for more than 2 hours.

Reheat only the amount you plan to eat. Warm the soup in a saucepan over low to medium-low heat, stirring often, until steaming hot. Milk-based soup can scorch if heated quickly or left unattended, and it may thicken after chilling; loosen it with a splash of milk or water as it warms. If using a microwave, heat in a microwave-safe bowl in short intervals, stirring between each one. Reheat leftovers to 165°F (74°C), checking with a food thermometer, and do not repeatedly cool and reheat the same batch. Freezing is possible, but the milk-based texture may separate or turn slightly grainy after thawing; whisk well while reheating and expect some change in smoothness.

Frequently Asked Questions

Is Finnish spinach soup traditionally served with egg?

Hard-boiled egg is a common and classic topping, often served as halves or wedges in the bowl. It adds a mild, substantial contrast to the soft spinach soup. It is still optional: the soup can be served on its own, and different households may choose different garnishes or seasonings.

Can I use fresh spinach instead of frozen?

Yes. Use about 1 lb (450 g) fresh trimmed spinach, wilt it, then cool, chop, and squeeze it before adding it to the soup. Fresh spinach is bulky before cooking, so do not judge the quantity by the volume of raw leaves. Its flavor may be a little brighter, while frozen chopped spinach is more finely textured and convenient.

Why did my soup turn out lumpy?

The flour may have clumped if the milk was added too quickly, or the roux may not have been whisked smoothly before the liquid went in. Start by whisking firmly over low heat; some small lumps will smooth out as the soup warms. For stubborn lumps, carefully blend the milk base before stirring in the spinach, taking care with hot liquid.

Can I make the soup ahead?

Yes. Prepare the soup up to 3 days ahead, cool it promptly, and refrigerate it covered. The texture may become thicker overnight, so add a little milk or water as you reheat it gently. For the best egg texture, cook and peel the eggs separately and add them to the bowls just before serving.

Can I make Finnish spinach soup vegan?

Yes. Use plant-based butter and an unsweetened, neutral plant milk, such as oat milk, in place of dairy milk. The flavor and texture will differ somewhat from the traditional milk-based version, and some plant milks are thinner or sweeter than others. Taste carefully for salt and seasoning, and omit the egg garnish or serve a suitable alternative on the side.

More recipes to cook

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

Spotted an error? Tell us and we will correct it (corrections policy).