Potato salad in mustard sauce

I will never forget the first time I tried to make this salad. I had about 4 sad-looking old potatoes rolling around in the drawer. I wasn't in the mood for anything serious to cook, but I still wanted something more substantial than a tomato and a slice of bread. And, honestly, I couldn't even imagine what mustard could do with some good potatoes and an onion. I laid everything out on the table and somehow got the proportions just right for my taste. Since then, I've made a few tweaks here and there, but the base has remained the same: simple, quick, and delicious. I won't say "cheap," or people might get upset, but it's exactly the kind of recipe I turn to when I'm out of inspiration or short on time.

Let me tell you quickly, it doesn't take much time or effort to make: about 30-35 minutes (depending on how quickly the potatoes boil, sometimes they feel like rocks). The quantities below yield about 3-4 normal servings, enough for a full meal, not like at a restaurant where you leave hungry. I won't lie, it's not rocket science; anyone can make it, even if they don't have much kitchen experience, so the level is "for all mortals."

I make it quite often, especially when I'm fasting or in a hurry. I don't have to watch the pot, and the kitchen doesn't fill with smoke. Moreover, it works great as a salad to take to work because it doesn't lose its flavor even after a few hours; in fact, it seems to taste even better after sitting for a bit. And, honestly, of all the potato salads I've tried, this one is one of the friendliest when it comes to using few and readily available ingredients. Oh, and if you don't feel like frying or complicating things with eggs, this is just what you need.

Here's what you need for this salad, including measurements, in case you're interested in getting it just right:

500 grams of potatoes (I prefer the regular ones, not too starchy, as they fall apart and I don't like that, but the pinkish ones work too)
100 grams of pitted olives – you can use sliced or whole ones, whatever you have on hand; I sometimes just throw them in as they come out of the package
1 medium onion – red onion works too, if you have it, it adds a nice flavor and color
3 tablespoons of plain mustard (not sweet, not grainy, just a classic mustard, like the most basic one from the supermarket)
about 80-100 ml of oil (a small cup – it depends on how much mustard you use, just eyeball it to get a creamy consistency)
salt to taste (I don't add it initially since the olives are salty)
freshly ground pepper, to your liking
a pinch of vegetable seasoning or salt for those who don't want seasoning – I don't judge anyone here, everyone has their own preferences

The potatoes are the star – they provide substance and keep you full, the olives add that salty flavor and a bit of texture, the onion cuts through the heaviness and adds a little "bite," while the mustard and oil dressing ties everything together with a bold flavor, so you don’t get bored. The pepper is to taste; sometimes I add a pinch of hot paprika if I'm in the mood.

Let me walk you through how I make it step by step:

1. I start by washing the potatoes well (especially if they have some dirt on them, so you don’t have surprises on your plate), then I throw them in a pot with their skins on and cover them with cold water. I also add a bit of salt to the water; I don't know why, but that's what all the old folks do, and they don’t seem to boil the same without it.
2. I let them boil for about 20-25 minutes. It depends on how thick the potatoes are, so I check with a fork towards the end – if it goes in easily, I take them out right away because I don’t want them turning to mush.
3. While the potatoes are boiling, I take care of the olives: I drain them well, rinse them a bit if they’re too salty, then slice them or leave them whole, depending on my mood. I peel the onion and slice it as thinly as I can (if it’s too pungent, I rub it with a bit of salt and set it aside).
4. Once the potatoes are boiled, I take them out and let them cool a bit, just enough to peel them without burning my fingers (but not too much, as the dressing won't stick well). I peel them and cut them into about 2 cm cubes, not too small, so they don’t fall apart.
5. Now comes the part I enjoy: the dressing. In a bowl, I put the 3 tablespoons of mustard, gradually add the oil while stirring with a wooden spoon or a fork, just like making mayonnaise, until it becomes creamy and thickens. Don’t worry if it doesn’t come together right away; mustard and oil do a good job without needing to be beaten to death.
6. In a large bowl, I put the potatoes, add the olives and onion, then pour the mustard dressing over everything. I mix gently so I don’t mash them.
7. I taste and only then add salt, pepper, and a bit of vegetable seasoning or vegetable salt. I don't add too much salt since the olives are already salty. If you want, you can also add a splash of vinegar, although I almost never do.

And that's it. You can let it sit for 10-15 minutes to blend the flavors, but usually, there’s no one around to wait that long.

Tips, variations, and serving ideas

Useful tips:
Don’t let the potatoes cool completely before mixing them with the dressing – when warm, they absorb the flavor better, and the dressing won’t just sit at the bottom of the bowl. If you buy the cheapest olives, rinse them with cold water; they can sometimes be too salty or bitter. Red onion is milder, but white onion works too if that’s what you have. A tip I learned from experience: don’t add all the oil at once to the mustard; it risks separating or becoming too difficult to mix. Try to incorporate it gradually.

Substitutions:
If you want to skip the oil entirely, you can use a plant-based yogurt or soy yogurt for those who are strict about calories or want a fat-free version. Vegetable seasoning can be replaced with celery salt or a little lemon juice for acidity. If you don’t have olives, you can use a few capers or, less commonly, finely chopped pickles – it’s not the classic recipe, but it tastes good.

Variations:
Some people add diced pickles; I do this in winter when I crave something tangy. It also works great with sliced radishes in the spring, adding a fresh note. For those not fasting, you can throw in a boiled egg sliced into rounds. I’ve also tried fresh parsley or even dill, and no one seemed to mind. If you want a spicy touch, add a sprinkle of chili or a bit of hot paprika.

Serving ideas:
I usually eat it as a main dish for lunch, with a slice of homemade bread. It also works as a side dish alongside grilled vegetables or, for those not fasting, baked fish. Some people pack it for work or picnics, especially since it doesn’t spill and doesn’t spoil easily. If you want something to drink with it, a cold lemonade or mint tea pairs wonderfully, and if you're in the mood for something alcoholic, a light beer is always welcome.

Frequently asked questions

Can it be made with sweet potatoes?
Yes, it works, but the final taste is completely different, sweeter, and you need to be careful not to boil them too much, as they can turn mushy easily. I’ve tried it twice, but I always go back to classic potatoes.

What type of mustard is suitable?
An ideal choice is plain mustard, not too spicy, but also not the one with a lot of sugar. If you use grainy mustard, the dressing will be more rustic and have a slightly crunchy texture, if that’s what you want. I say any mustard you already have open in the fridge will work for this recipe.

Can I use olive oil instead of sunflower oil?
Sure, if you like the flavor. But keep in mind it will have a stronger taste; not everyone appreciates it in this recipe as it can overpower the mustard. I’ve used a mix of half and half, and it was fine, but I didn’t like it with just extra virgin olive oil; it was too strong for my taste.

Can the salad be made a day in advance?
Yes, but be aware that the onion will soften, and the flavors will meld more. Sometimes the olives can slightly color the potatoes, but it doesn’t affect the taste. If you keep it covered in the fridge, you won’t have any worries.

What do I do if I don’t have vegetable seasoning?
Just skip it, or add a bit of vegetable salt, regular salt, or even a teaspoon of lemon juice for a bit of acidity. It’s really not a core ingredient, more for those who want that "home-cooked" flavor.

What if the dressing doesn’t come together?
It doesn’t have to be like mayonnaise; it just needs to be creamy. Mix the mustard and oil patiently; if it doesn’t come together, add a little more mustard. In any case, once you mix it with the potatoes, it will come together in the salad.

Nutritional values (approximate)

For one serving of salad (about 250g), I estimate it has around 250-300 kcal. The potatoes contribute most of the carbohydrates, about 35-40g per serving. The oil adds about 8-10g of fat, while the mustard and olives add another 2-3g of protein. If you’re watching calories, you can reduce the oil or use a light mustard, but it won’t be as creamy. It’s filling but won’t make you gain weight if you don’t eat half a bowl by yourself. The salt and olives add some sodium, so be mindful if you have high blood pressure. Overall, it’s a balanced meal, with plenty of fiber from the potatoes and onion, without animal fats and gluten, unless you add bread on the side.

How to store and reheat

This salad keeps well in the fridge, in a covered container or even in a bowl with a plate on top (that’s what I do when I don’t feel like washing containers). It lasts 2-3 days without issues, and sometimes the next day, all the flavors seem to meld even better. I never heat it; it’s a salad that’s meant to be served cold or at room temperature – if you heat it, the dressing separates, the potatoes become mushy, and the onion loses its charm. If you find yourself without olives at the bottom of the bowl, you can always add fresh ones when serving. I like to give it a quick stir before putting it on the plate, as the dressing tends to settle at the bottom. Honestly, it rarely lasts more than a day and a half at my place; it disappears quickly.