This is a five-ingredient vinaigrette โ olive oil, fresh lemon juice, wholegrain mustard, white onion, salt and pepper โ that comes together in under five minutes with no equipment beyond a bowl and a whisk. The mustard does real work here: it emulsifies the oil and lemon juice so the dressing actually clings to leaves instead of pooling at the bottom of the bowl. If you want a dressing you can throw together on a weeknight and use across multiple meals, this is a solid one to keep in rotation.
Before you start
The single technique that matters most is the order you add ingredients. Whisk the lemon juice and mustard together first, then pour in the olive oil in a slow, steady stream while whisking continuously. This gives the mustard time to bind the two liquids into a stable emulsion rather than a separated, oily puddle. The second thing worth knowing: thinly sliced white onion is sharp and pungent raw, so if you want a milder bite, soak the slices in cold water for five minutes before adding them to the dressing โ it takes the edge off without losing the flavor entirely.
Shopping notes
- Wholegrain mustard: The recipe calls for wholegrain specifically, and it matters โ the whole seeds add texture and a slightly milder, nuttier flavor than smooth Dijon. Dijon works as a swap and will give you a sharper, more pungent result. Yellow mustard is too sweet here; skip it.
- Lemon: Use a fresh lemon, not bottled juice. Bottled juice is more acidic and flat-tasting; fresh juice has brightness that bottled canโt replicate. One medium lemon gives you roughly 2โ3 tablespoons of juice.
- Olive oil: Extra virgin is specified, and itโs worth using โ the flavor is part of the dressing, not just a carrier.
Troubleshooting
- Dressing separates immediately: You added the oil too fast. Next time, whisk the lemon juice and mustard into a paste first, then drizzle the oil in slowly. If itโs already separated, whisk it hard again โ it will usually come back together.
- Too sharp or acidic: Add another half tablespoon of olive oil and whisk again. A small pinch of sugar can also balance excess acidity without making the dressing taste sweet.
- Onion flavor is overwhelming: The onion slices are meant to sit in the dressing and mellow, but raw white onion is strong. Soak slices in cold water for 5โ10 minutes before adding, or swap to a milder shallot.
- Dressing tastes flat: Salt is almost always the answer. Add a small pinch, whisk, and taste again. Under-seasoned dressing makes the whole salad taste dull regardless of how good the greens are.
- Greens are wilted before serving: Dress it at the table โ a pre-dressed salad goes limp fast. Keep the dressing in a jar and pour it on right before eating.
Storage and make-ahead
The dressing itself keeps well. Store it in a sealed jar in the refrigerator for up to five days. The olive oil will solidify slightly when cold โ thatโs normal. Pull it out ten minutes before you need it and shake or whisk it back together. The onion slices will continue to soften and mellow in the dressing over time, which is actually an improvement after day one. Do not dress your salad in advance; add the dressing only when youโre ready to eat. Dressed greens sitting in acid and oil for more than a few minutes go soft and unappetizing fast, especially delicate lettuces.
Tangy Lemon and Mustard Vinaigrette Dressing
Ingredients
- ยฝ medium white onion thinly sliced
- 6 tablespoons olive oil extra virgin
- 1 medium lemon juiced
- 1 teaspoon mustard wholegrain
- 1 teaspoon salt
- 1 teaspoon ground black pepper cracked
Instructions
- To make the lemony vinaigrette combine the olive oil, lemon juice, mustard and season to taste with salt and pepper. Once mixed, add the onion slices and set them aside.
- Pour onto your fresh vegetable salad.
Nutrition
Frequently asked questions
Can I use lime juice instead of lemon?
Yes, lime juice works as a direct swap in the same quantity. The flavor will be slightly more tropical and a touch less sharp than lemon, but the dressing will still emulsify and balance well with the mustard.
How do I make this dressing more filling as part of a meal salad?
The dressing itself is 201 calories per serving, mostly from olive oil, so it adds substance. To build a meal around it, toss it with a base that has protein and bulk โ chickpeas, white beans, hard-boiled eggs, or grilled chicken all work well with lemon and mustard flavors.
Can I make this without the onion?
Yes. The onion adds mild sharpness and texture but the dressing is complete without it. Leave it out if you want a cleaner, simpler vinaigrette that works across more salad types.
Is this dressing vegan?
Yes, all five ingredients โ olive oil, lemon juice, wholegrain mustard, white onion, salt and pepper โ are plant-based. No swaps needed.
My dressing always tastes too oily. Whatโs the ratio issue?
This recipe uses a 6:1 ratio of oil to lemon juice, which is on the richer side. If it tastes heavy, reduce the oil to 4 tablespoons and keep everything else the same โ the mustard will still emulsify it. Taste and adjust from there.