Break the nougat bar into small pieces. Heat the heavy cream in a small saucepan over low heat, without bringing it to a boil. Dissolve the gelatin packet in the milk and add it to the saucepan with the cream, stirring constantly. Add the nougat while continuing to stir.

Remove the cookie base from the fridge, which we prepared earlier as follows: Crush the cookies and mix them with melted butter until you get a dough.

Place in a springform pan and refrigerate. Carefully pour the previous mixture over the cookie base and let it cool in the fridge. Melt the chocolate, let it cool slightly, and pour it over the nougat mousse base before serving.