Classic Hungarian French salad: tender diced potatoes, carrots, green peas, gherkins, and tart apple bound in a tangy mayonnaise, mustard, and sour cream dressing.
Ensure cooked diced potatoes, carrots, and green peas are completely chilled. Pat diced pickled gherkins dry with paper towels.
In a large bowl, whisk together the mayonnaise, thick sour cream, mustard, fresh lemon juice, salt, and white pepper until completely smooth.
Add the diced potatoes, carrots, peas, gherkins, and diced apple to the dressing. Fold together gently with a spatula so the vegetables hold their neat shape.
Cover and chill for at least 1 hour before serving to let flavours meld. Serve chilled as an accompaniment to roast meats or festive platters.