Preheat oven to 350°F (175°C). Grease and line a 9×13-inch pan with parchment paper.
In a medium bowl, sift or whisk together the flour, baking powder, and salt until well combined. Set aside.
In a large bowl using an electric mixer, beat the softened butter and granulated sugar together on medium-high speed until the mixture is light, pale, and fluffy (about 3-4 minutes).
Add the eggs one at a time, beating well after each addition. Mix in the vanilla extract.
With the mixer on low speed, add the dry ingredients in three additions, alternating with the milk in two additions (Dry, Milk, Dry, Milk, Dry). Mix until just combined; do not overmix.
Pour the batter into the prepared pan and spread evenly with a spatula. Bake for 25-30 minutes, or until a toothpick inserted into the center comes out clean.
Let the cake cool in the pan for 15 minutes before transferring to a wire rack to cool completely before frosting.
