Lemon Ice Box Cake

I used to make this all the time and it went over really well everytime I took it somewhere. It is a great summer dessert. I don't make it as often but when I do, you can't get enough of it! It is also really simple to make.

1 box yellow or white cake mix (whichever you prefer) & ingredients to make
1 can Condensed milk
1 8 oz. container Cool Whip
1/4 cup lemon juice

Prepare cake mix as directed for a 2 layer cake. When cool, slice layers in half to make 4 layers. Mix milk & lemon juice. To assemble, spread lemon mixture between each layer, reserving some. Mix reserved mixture with cool whip. Frost cake with cool whip mixture. Garnish with lemon slices.

Keep refrigerated!