Preheat your oven to 350°F (175°C) and grease a 13×18-inch baking sheet.

In a large bowl, whisk together flour, sugar, baking powder, and salt.

Add milk, vegetable oil, eggs, and vanilla extract; mix until just combined.

Pour batter into the prepared pan and bake for 20-25 minutes or until golden brown and a toothpick comes out clean.

For the frosting, beat cream cheese and butter until creamy.

Gradually add powdered sugar and enough milk to achieve desired consistency.

Once the cake is cool, frost with the cream cheese mixture.