Potato Salad with Celery and Herbs

Place the potatoes in a large pot, cover with cold water and bring to a boil. Add 2 teaspoon salt, reduce heat, and simmer until the potatoes are just tender, 10 to 15 minutes. Drain and run under cold water to cool. Cut the potatoes in half or quarter if large. Meanwhile, grate 2 teaspoon lemon zest into a large bowl, then squeeze in the juice (you should have about 3 tablespoons juice total). Whisk in the oil, mustard, and 1/4 teaspoon each salt and pepper. Add the potatoes and celery to the bowl and gently toss to coat. Fold in the parsley and dill and top with the eggs, if desired.