In the bowl of a stand mixer, cream together the butter and cream cheese until mixed thoroughly.
Scrape the sides of the bowl and then add the remaining ingredients, adding a portion of the powdered sugar and then letting the mixer go on low until the powdered sugar is completely incorporated before adding more.
Repeat this process until all of the powdered sugar has been added.
Mix in the lemon bakery emulsion or extract and the pinch of salt.
You can adjust the consistency of the frosting by adding a touch of milk to thin the frosting or more powdered sugar to thicken the frosting. (I generally add NO liquid).
Enjoy! Use on cakes, cookies, brownies or simply eat by the spoonful.