Combine the cream cheese, mayonnaise, sour cream, and garlic in a mixing bowl. Add the Asiago cheese and parsley; mix well. Press as much moisture out of the spinach as you can; stir into the mixture. Spread into the bottom of an 8 1/2 x 10 baking dish.
Bake in the preheated oven until the middle is bubbling and the edges are golden brown, 20 to 25 minutes.
