Preheat oven to 350°F (175°C). Grease and flour two 9-inch round cake pans, or line with parchment paper.
In a bowl, whisk together flour, baking powder, and salt. Set aside. In a large mixing bowl, beat the softened butter and sugar until light and fluffy, about 3 minutes.
Beat in the eggs one at a time, ensuring each is fully incorporated. Stir in the vanilla extract.
Gradually add the dry ingredients in three additions, alternating with the milk in two additions, starting and ending with the dry ingredients. Mix until smooth.
Divide the batter evenly between the two pans and smooth the tops. Bake for 30-35 minutes, or until a toothpick inserted into the center comes out clean. Allow the cakes to cool in the pans for 10 minutes, then transfer to a cooling rack to cool completely.
Beat the softened butter in a mixing bowl until creamy. Gradually add the powdered sugar, vanilla extract, milk, and a pinch of salt, beating until smooth and fluffy.
Once the cakes are fully cooled, spread a layer of frosting on top of one cake, place the second cake on top, and frost the top and sides of the cake.
Slice and enjoy your homemade Magnolia Bakery vanilla cake!