Dipping sauce

The classic dipping sauce found on every Vietnamese table. You can change the sauce to suit: add grated ginger, shredded carrot or white radish (mooli); use all lime juice and no vinegar; go more pungently Vietnamese and beat in a teaspoon of toasted shrimp paste; and for a milder sauce, stir in 2 tbsp water or coconut water - ideal for the dipping sauce to rice-paper-wrapped rolls. Makes a fab oil-free (= fat-free) salad dressing too.