Preheat oven to 375F degrees. Give the spinach a rough chop.
Heat the oil in a large pan over medium-low heat. Saute the garlic for 1 minute. Add the spinach and saute until wilted. Remove from heat and drain out any excess liquid.
In a mixing bowl, combine the cream cheese, sour cream, Parmesan cheese and salt. Fold in the spinach.
Transfer the spinach mixture to a baking dish. Sprinkle mozzarella cheese over top. Bake 25 minutes, until the top is golden brown and bubbling.