Spray a 9-ich springform pan or 9 by 9 baking dish with cooking spray. (Note the dish looks more dramatic when made in a springform pan but is every bit as delicious made in a casserole or baking dish and is easier to serve.)
Beat the cream cheese until smooth. Add the dulce de leche and beat until fully incorporated.
Combine the coffee and chocolate liqueur (if using) in a shallow bowl or pie plate. One by one, dip the cookies into the coffee briefly and place in the prepared pan, using broken pieces to fill in any gaps. Layer half of the dulce de leche mixture on top and spread evenly. Repeat with another layer of cookies and then the rest of the dulce de leche mixture. Dust with cocoa powder or decorate with chocolate curls. Refrigerate at least 4 hours. Can be prepared a day ahead.
Remove from the springform pan, place on a cake stand or plate, and serve.
*To make chocolate curls, microwave a chocolate candy bar for 10 seconds, then scrape the sides with a vegetable peeler.