Crush the chocolate sandwich cookies in a food processor or with a rolling pin. Set aside.
In a saucepan over low heat, add half a cup of heavy cream and half a cup of chocolate chips. Stir until melted together. Remove from heat and set aside.
In a kitchen mixer, beat one and a half cups of heavy cream until soft peaks form. Halfway through, begin adding the sugar, a little at a time. Once the soft peaks form, split the cream into two bowls.
In one bowl, fold in melted chocolate a little a time until the chocolate is incorporated.
In the second bowl, slowly fold in about one-half cup of Bailey’s Irish Cream. Be careful not to break the cream with too much liquid.
In glasses or mason jars, layer the chocolate mousse, cookie crumbs, Bailey’s cream, chocolate mousse, Bailey’s cream, and cookie crumbs. Refrigerate for 1-3 hours, or overnight, before serving.