With an electric mixer, cream together the butter and sugar until it is light and fluffy. (about 2-3 minutes) Mix in the lemon juice (or True lemon packs)
Beat in the vanilla and the eggs.
In a separate bowl, sift together the flour, cream of tartar, baking soda, and salt.
Gradually add the flour mixture into the butter mixture.
Chill the dough for 4 hours or overnight
Roll out the dough on a floured surface and use cookie cutters. Transfer the cookies onto an ungreased cookie sheet.
Bake at 350° for 6-8 minutes, until they are pale golden brown.
Let the cookies cool before frosting!