In mixer fitted with paddle attachment and set on higest speed, cream together butter, sugar, and salt until light and fluffy.
Add lemon zest. Beat briefly.
Add eggs, one at a time. Beat well after adding each egg.
In separate bowl, mix together milk and lemon extract.
In another bowl, mix together flour and baking powder.
Add ⅓ of dry mix to butter mix. Beat briefly at lowest speed.
Add ½ of wet mix. Beat briefly at lowest speed.
Add ½ of remaining dry mix. Beat briefly at lowest speed.
Add remaining wet mix. Beat briefly at lowest speed.
Add remaining dry mix. Beat briefly at lowest speed.
Pour cake batter into buttered and floured Bundt pan.