Preheat your oven to 350°F (175°C). Grease and flour a 9-inch round cake pan.
In a large bowl, cream the butter and sugar until light and fluffy.
Add the eggs one at a time, beating well after each addition.
In another bowl, whisk together the flour, baking powder, and salt.
Gradually add the dry ingredients to the butter mixture, alternating with the milk. Start and end with the dry ingredients.
Stir in the vanilla extract.
Pour the batter into the prepared pan and smooth the top.
Bake for 30 minutes or until a toothpick inserted into the center comes out clean.
Allow the cake to cool in the pan for 10 minutes, then turn it out onto a wire rack to cool completely.