Preheat oven to 350 degrees F (175 degrees C). Grease and flour a 9 inch cake pan.
In a bowl, cream together the sugar and butter. Beat in the eggs, one at a time, then stir in the vanilla and salt to this mixture.
Combine flour and baking powder, add to the creamed mixture and mix well.
Stir in the milk until batter is smooth. Pour batter into the prepared pan.
For the Frosting - Cream room temperature butter with the paddle attachment of a bowl of the mixer.
Slowly beat in confectioners' sugar until fully incorporated. Beat in vanilla extract.
Pour in milk and beat for an additional 3-4 minutes. Add you favourite food coloring, and beat for few seconds until smooth.
We make 6x butter cream recipe to decorate one cake.