Bottom: Mix the 4 first ingredients together. Put in a greased 9x9 baking pan (grease the sides also). Cook in the oven at 350 F for 10 minutes.
Second Layer: In a clean bowl, mix coconut and condensed milk. Spread this mixture on the bottom, in the pan. Cook in the oven at 350 F for 20 minutes, or until the cookie begins to golden on the sides. Let cool before icing.
Icing: Beat all ingredients of the icing together, adding juice, if needed to have a good consistency. Put the icing on the cold cookie. Put in an hermetic container and let rest at least one day to let the cookie soften. You can eat the squares the same day but they're harder to cut when fresh.