Preheat oven to 350 degrees. Line the bottom of a 9X13-inch pan with parchment paper or aluminum foil. If using foil, spray lightly with cooking spray.
Unroll one tube of crescent roll dough and stretch it to cover the bottom of the pan. Bake for 5 minutes. Let cool.
Using an electric mixer, beat cream cheese and lemon juice until smooth. Set aside about 1 teaspoon of lemon zest and add the rest to the cream cheese mixture along with the 1/2 cup sugar and vanilla extract. Beat until mixed well.
Spread cream cheese mixture on top of bottom layer of dough.
Unroll second piece of dough and lay it on top of cream cheese, stretching it to fit.
Brush top with melted butter. Combine the 3 tablespoons of sugar and the set aside lemon zest and sprinkle on top.
Bake for 30 minutes, or until golden brown. Let cool 20 minutes. Cut into squares and refrigerate until chilled.