At least 1 hour before serving, whisk the olive oil, lemon zest, 2 tablespoons of lemon juice, shallot (or garlic), celery seed, celery salt, miso, and a big pinch of salt and pepper in a small bowl. In a large bowl, toss the celery and apple with the remaining tablespoon of lemon juice. (According to Ina, even though there is lemon juice in the dressing this step makes a difference, and I believe everything Ina says.) Add half of the dressing and toss. Cover and refrigerate until ready to serve.