Mix the mayonnaise and some water with the whisk until creamy. Add vinegar, cut the onion into small cubes and mix in. Add lettuce herbs (e.g. freeze-dried from the jar). Season to taste with salt, pepper, paprika powder and curry.
I eat this dressing e.g., on lettuce with tomatoes, cucumber, tuna, boiled ham, eggs, crabs and grated Gouda cheese.