Take four croissants and make a horizontal cut in the middle of each one, using a sharp knife. Leave the top and bottom of each croisssant half connected. Leave aside.
In small bowl, combine, using spoon, Ricotta, vanilla extract, lemon zest, chocolate chips and powdered sugar.
Butter 7 x 5 inches baking dish.
Fill the croisssants and place them into the dish.
Glaze the croissants with egg, using kitchen brush.