In a medium mixing bowl, beat cream cheese until smooth and lump free.
Add condensed milk a little bit at a time, mixing as you go.
Once the condensed milk is incorporated, stir in the lemon juice.
Chill for one hour to allow the frosting to thicken up.
Spread over cake.
Store in the refrigerator.
Notes
For a thicker frosting, stir in a cup of powdered sugar.For a bolder lemon flavor, add lemon zest or 1/2 teaspoon lemon extract.Use full fat cream cheese.