Preheat the oven to 350°F. Grease and flour a standard size loaf pan.

Using a mixer fitted with the whisk attachment, cream the softened butter and granulated sugar until light and fluffy, about 2 minutes.

Add the eggs one at a time, beating well after each addition. Stir in the vanilla extract.

In another bowl, whisk together the flour, baking powder, and salt.

Gradually add the dry ingredients to the wet mixture, alternating with the sour cream and milk, starting and ending with the flour mixture. Mix until just combined.

Transfer the batter to the prepared pan and smooth the top with a spatula. Bake for 50-60 minutes, or until a toothpick inserted into the center comes out clean.

Let the cake cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.