Make the dressing: In a food processor, purée the carrot, ginger, olive oil, rice vinegar, soy sauce, sugar, onion powder, a pinch of salt and 1 tablespoon cold water until as smooth as possible, 1 to 2 minutes.

Dress the salad: Place the lettuce leaves in a large serving bowl. Add a couple of tablespoons of the dressing and toss, then add more as needed to evenly coat. The salad should be lightly dressed, not drowned; don’t use every drop of dressing if you don’t need to. Taste for seasoning, adjusting with more salt as desired. Top the salad with the mint leaves and serve immediately.