Place oven rack in middle position and preheat oven to 350 degrees.In a medium bowl, beat the cream cheese and butter until nice and fluffy, about 90 seconds using a hand mixer on the low setting.
2 tablespoons cream cheese, ¼ cup butter
Beat in the sugar until well blended or "creamed."
½ cup sugar
Beat in the egg.
1 egg
Mix the flour, salt, and baking soda in a small bowl, then add to the batter mixture.
¼ teaspoon baking soda, ¾ cup flour, ⅛ teaspoon salt
Add the lemon juice, lemon zest, and milk. Mix to combine well.