Preheat oven to 350 degrees. Spray 9x13 baking pan with non-stick cooking spray.
In a medium bowl, cream the butter and sugar with a mixer until creamy. Add eggs, baking powder and salt and mix until combined. Slowly add in milk and flour, alternating each, and mixing in between. Beat until combined. Stir in vanilla.
Pour batter into greased 9x13 baking pan, spreading evenly. Bake for 18-19 minutes or until toothpick comes out clean. Cool completely.
In a medium bowl, beat together the cream cheese and powdered sugar until smooth. Mix in frozen Cool Whip, or fresh whipped cream. Stir in the zest of 1 large lime. Spread evenly over cooled shortcake.
Add the juice of the 1 lime to the sliced strawberries. Stir, and spread evenly over the cream mixture. Cover and refrigerate for about 3 hours to set. For added color just before serving, add more lime zest if desired.
I have made this with regular full flavor ingredients, and also using reduced fat/sugar/sugar free ingredients. I found that some of the sugar free ingredients such as the Cool Whip did not hold up well, and become soupy. I would suggest regular Cool Whip, or even making your own fresh whipped cream which I will be trying next time!