Kohlrabi Potato Salad with Creamy Mustard Dressing

Kohlrabi potato salad combines tender potatoes and crisp-tender kohlrabi with a creamy dressing of mustard, sour cream, vinegar, and fresh dill. It makes a cool, tangy side dish for picnics and weeknight meals, and the vegetables can be cooked ahead so the flavors have time to mingle.

Ingredients

2 lb (900 g) waxy potatoes, such as Yukon Gold or red potatoes
3 medium kohlrabi bulbs, about 1 lb (450 g) after trimming
1½ tsp fine salt (9 g), divided, plus more for the cooking water
½ cup mayonnaise (120 ml)
⅓ cup sour cream (80 g)
1 tbsp Dijon mustard (15 ml)
1½ tbsp apple cider vinegar (22 ml)
1 tsp granulated sugar (4 g)
¼ tsp freshly ground black pepper (about 0.5 g), plus more to taste
⅓ cup finely diced red onion (about 50 g)
1 cup finely diced celery (about 100 g)
2 tbsp chopped fresh dill (about 6 g), plus a little extra for serving if desired
2 tbsp chopped fresh parsley (about 8 g), optional

Instructions

Prepare the vegetables and dressing. Scrub the potatoes. Peel the kohlrabi bulbs, removing the tough outer skin and any fibrous patches; a sturdy vegetable peeler may take several passes, especially near the stem end. Cut the potatoes into roughly 1-inch (2.5 cm) pieces and the kohlrabi into ¾-inch (2 cm) cubes so both cook evenly. In a large bowl, whisk together the mayonnaise, sour cream, Dijon, vinegar, sugar, 1 teaspoon of the salt, and the pepper. Stir in the onion, celery, dill, and parsley if using. Set the dressing aside while you cook the vegetables.
Cook the potatoes. Put the potato pieces in a large pot and cover them with cold water by about 1 inch (2.5 cm). Add a generous pinch of salt. Bring the water to a boil, then lower the heat to maintain a steady simmer. Cook for 12–16 minutes, checking a piece with a small knife after 12 minutes. It should be tender through the center but still hold its shape; if the edges are crumbling, it has cooked too long. Drain well.
Cook the kohlrabi. While the potatoes cook, bring a second pot of salted water to a boil. Add the kohlrabi cubes and simmer for 8–10 minutes, until a knife slips into a cube with slight resistance. Kohlrabi should be tender enough to eat comfortably but not mushy. Drain it thoroughly. Cooking it separately lets you check its texture without overcooking the potatoes.
Cool the vegetables briefly. Spread the drained potatoes and kohlrabi on a rimmed tray or in a wide shallow bowl for 10 minutes, just until they are no longer steaming heavily. This short rest helps excess moisture evaporate and keeps the dressing from turning watery. Don’t rinse them under cold water, since that can wash away flavor and leave the surfaces wet.
Dress and season. Add the warm-but-not-hot vegetables to the bowl of dressing. Fold gently with a flexible spatula until each piece is coated, taking care not to crush the potatoes. Taste and mix in the remaining ½ teaspoon salt, or more, as needed. The dressing may taste slightly sharp at first; the potatoes absorb some of its seasoning as the salad chills.
Chill before serving. Cover the bowl and refrigerate for 45 minutes. Give the salad a careful stir, taste again, and adjust with another splash of vinegar, a pinch of salt, or a little pepper if the flavors seem muted. Scatter extra dill over the top and serve cold or cool.

Tips

Choose potatoes that stay intact. Waxy red potatoes and Yukon Golds hold their shape better than very starchy russets. If russets are what you have, cut them into larger pieces, check them early, and fold them into the dressing especially gently. A few broken edges are fine, but too much stirring can turn the salad pasty.
Peel kohlrabi generously. The outer layer can be woody, even when the inside is tender. Peel until you reach pale, moist flesh, and trim away any tough fibers around the base. If a bulb is especially large or mature, taste a small raw piece after peeling; if it seems fibrous, cut away the firm outer band before cubing.
Drain and cool well. Water clinging to the vegetables dilutes the creamy dressing. Let them drain for a minute, then give them time to release steam before mixing. Dress them while slightly warm rather than piping hot: they take on the seasoning, but excess heat is less likely to make the mayonnaise dressing loose.
Balance the dressing after chilling. Cold food can taste less seasoned than it did at room temperature. Taste the salad just before serving and make small adjustments. Add salt in pinches, and use vinegar a teaspoon at a time so the finished dressing stays tangy rather than harsh.

Serving Suggestions

Serve this salad cold or cool as a substantial side for grilled vegetables, roasted chicken, sausages, or a simple sandwich. Its creamy, sharp dressing works particularly well beside smoky or savory main dishes, while the kohlrabi gives the familiar potato-salad texture a fresher, lightly crisp note. For a picnic or buffet, keep the serving bowl nested in a larger bowl of ice and return leftovers to the refrigerator promptly.

For a lighter meal, spoon it onto a plate with leafy greens, sliced cucumber, and crusty bread. It also fits easily into a make-ahead lunch: pack the salad in a chilled container and add a few extra dill fronds just before eating. If serving a crowd, garnish the top with herbs rather than stirring them all in; the green flecks look fresh and make it easy to identify the salad on a shared table.

Variations

Make it more herb-forward: Increase the dill to 3 tablespoons (about 9 g), or replace half of it with chopped chives. Chives give the salad a mild onion flavor, while dill keeps the dressing bright and particularly suited to kohlrabi. A small handful of chopped celery leaves can also be used in place of some parsley.

Use a sharper, less rich dressing: Replace the sour cream with plain yogurt, or use ¼ cup (60 ml) yogurt and add an extra teaspoon of mayonnaise for body. Yogurt makes the dressing tangier and a little thinner, so add it gradually and taste before adding more vinegar. For a fully dairy-free version, use a plant-based sour cream or unsweetened plant-based yogurt with dairy-free mayonnaise.

Add crunch or a pickle note: Stir in ¼ cup (35 g) finely chopped cornichons or dill pickles, then reduce the vinegar slightly at first and adjust after tasting. Toasted sunflower seeds can be sprinkled over individual servings for crunch; add them at the table so they do not soften in the dressing. Keep additions modest so the potato and kohlrabi remain the focus.

Adjust the vegetables: If you have only two kohlrabi bulbs, use about 12 oz (340 g) trimmed kohlrabi and add another 8 oz (225 g) of potatoes. You can also replace up to half the potatoes with cooked carrots or blanched green beans. Those vegetables bring extra sweetness or a firmer bite, so taste the salad after chilling and adjust the mustard and vinegar accordingly.

Storage and Reheating

Transfer the salad to a covered container and refrigerate it within 2 hours of serving. It keeps for 3–4 days in the refrigerator; the vegetables may soften slightly over time, and the dressing can thicken as it chills. Stir gently before serving, and refresh the flavor with a little chopped dill or a teaspoon of vinegar if needed. Do not leave the salad at room temperature for more than 2 hours, or more than 1 hour if the temperature is above 90°F (32°C).

This is designed to be served cold or cool, so reheating is not necessary and can make the dressing separate. If you choose to warm a portion, heat it until leftovers reach 165°F (74°C), as recommended by USDA FSIS, and expect a softer texture. For the best make-ahead result, cook and drain the vegetables, cool them, and refrigerate them separately from the dressing for up to a day; combine and chill the salad before serving.

Frequently Asked Questions

What does kohlrabi taste like in potato salad?
Kohlrabi has a mild, gently sweet flavor often compared with a mix of cabbage stem and broccoli stem, without the strong taste of either. Once cooked until just tender, it takes on the mustard-dill dressing while keeping a slightly firmer bite than potato. Peel it well so the salad does not have tough or fibrous pieces.

Can I make kohlrabi potato salad ahead?
Yes. You can make it the day before and keep it covered in the refrigerator. It is best after at least 45 minutes of chilling, and the flavor continues to settle overnight. Before serving, stir gently and taste for salt and acidity; cold potatoes sometimes need a small seasoning adjustment.

Do I have to peel the kohlrabi?
For this salad, peeling is recommended because the outer skin and the layer just beneath it can be tough, particularly on larger bulbs. Remove the skin with a vegetable peeler or paring knife until the flesh looks pale and feels tender. Very small, young kohlrabi can have a more delicate skin, but peeling still gives the most consistent texture.

Can I cook the potatoes and kohlrabi in the same pot?
You can, but their cooking times differ. If using one pot, add the potatoes first and simmer them for about 6 minutes before adding the kohlrabi; then check each vegetable separately for tenderness. Drain as soon as each is ready. Separate pots make it easier to avoid overcooking one while waiting for the other.

Why did my potato salad turn watery?
Wet vegetables, potatoes that have been overcooked, or watery sour cream can thin the dressing. Drain both vegetables thoroughly and let steam escape before mixing. If the salad is already loose, chill it first, then stir in a spoonful of mayonnaise or sour cream. Avoid adding extra vinegar until you have checked the texture and tasted it again.

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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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