Preheat your oven to 350°F (175°C). Grease and flour a cake pan.
In a mixing bowl, cream together the butter and sugar until light and fluffy.
Add the eggs one at a time, beating well after each addition.
In another bowl, sift together the flour, baking powder, and salt.
Gradually add the dry ingredients to the butter mixture, alternating with the milk. Begin and end with the dry ingredients. Mix in the vanilla extract.
Pour the batter into the prepared cake 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 out onto a wire rack to cool completely.