Preheat oven to 350°F (175°C). Grease and flour an 8-inch square baking dish.
Sift together the flour, baking powder and salt; set aside.
In a large bowl, beat together the sugar and butter until light and fluffy. Beat in the eggs one at a time, then beat in the milk
Add the dry ingredients to the wet ingredients and beat until well blended. Pour batter into prepared dish.
Bake cake for 35 minutes, or until a toothpick inserted into the center comes out clean.
Cool cake completely before frosting.
To frost, combine evaporated milk, heavy cream and vanilla extract in a small bowl. Frost cake with evaporated milk mixture.