Ingredients :

• Plain yogurt — The foundation. Avoid 0% fat yogurt — it makes the sauce too watery and slightly bitter on the palate. A classic whole milk yogurt or a low-fat Greek yogurt is what you need. If you only have fromage blanc on hand, that works too; the texture will just be a bit denser and less tangy.
• Fresh lemon — Must be fresh. Bottled juice has that metallic taste that you notice immediately in such a simple sauce. A direct squeeze from half a lemon, filtering the seeds with your fingers, is more than enough. Add gradually, as the acidity of yogurt varies by brand.
• Dijon mustard — This is what gives the sauce its kick. A basic supermarket mustard works just fine. What we often forget: it also acts as a natural emulsifier — it’s thanks to the mustard that the sauce stays bound and smooth rather than separating after two minutes.
• Olive oil — One spoonful, no more. It softens the lemon’s acidity and brings a subtle roundness to the palate that you wouldn’t expect until you taste it. No need for a premium oil here — your everyday bottle is perfect.