Ruth’s bills itself as a “kosher vegetarian” joint, but you will also find fish on the menu. It’s small (around 12 tables), so book ahead if you want to be certain of a table. The interior is cafelike and informal, the menu likewise. Skip the Italian primi and go right for Eastern Mediterranean secondi such as vegetarian couscous with harissa or fish moussaka, a layered bake of eggplant, tomato, salmon, and spiced rice served with salad and caponata (a cold vegetable preserve). A rabbi from the adjacent synagogue oversees the kosher credentials.