Preheat Oven: Preheat the oven to 350°F (175°C). Grease a 9×13-inch baking dish.
Prepare Cake Batter: In a large mixing bowl, combine the undrained pineapple, flour, sugar, eggs, and baking soda. Mix until smooth.
Bake the Cake: Pour the batter into the prepared baking dish and bake for 30-35 minutes, or until the top is golden brown and a toothpick inserted into the center comes out clean.
Cool the Cake: Let the cake cool in the pan for about 15 minutes.
Make the Icing: Beat together the softened cream cheese and butter until smooth. Gradually add the powdered sugar, vanilla extract, and milk, beating until smooth and spreadable.
Ice the Cake: Spread the icing evenly over the top of the warm cake. Allow the cake to cool completely before serving.