While not a traditional pickle, the way lemon juice is used in this recipe’s dressing acts like a “quick pickle” for the fresh coriander, transforming its flavour and preserving its vibrancy. This acidic element is the key to the sauce’s bright, punchy character.
When the fresh coriander is blitzed with the lemon juice, the acid begins to work on the herb’s cell walls. This action helps to release its aromatic oils, intensifying its citrusy, fresh flavour throughout the dressing.
The lemon juice also plays a crucial role in balancing the richness of the other ingredients. Its sharp, zesty acidity cuts through the fat of the olive oil, egg yolk, and parmesan, preventing the dressing from tasting heavy or cloying. It provides a necessary “lift” to the entire sauce.
Finally, the acid helps to keep the dressing’s vibrant green colour brighter for longer. This is a perfect example of how a simple acidic ingredient like lemon juice can be a multi-functional powerhouse in a recipe.