Coffee-flavored icebox cake layers María cookies with a rich mocha cream. This family-friendly dessert is a smooth, aromatic, elegant no-bake treat for coffee lovers.
In a small bowl, dissolve instant coffee powder in hot water until smooth; stir in vanilla extract and let cool completely before using.
In a large bowl, combine sweetened condensed milk, evaporated milk, and heavy cream; whip with a hand mixer on medium-high speed until mixture thickens slightly, about 2–3 minutes.
Add the cooled coffee mixture into the cream base and beat for 1 more minute on medium speed until fully combined and lightly fluffy.
Dip each María cookie quickly into cold milk (optional, not included in ingredient list) to soften, then arrange a single layer of cookies on the bottom of a square or rectangular baking dish.
Spread one-third of the coffee cream evenly over the cookies; repeat layering cookies and cream two more times, finishing with a smooth layer of coffee cream on top.
Cover tightly with plastic wrap and refrigerate for at least 4 hours (preferably overnight) for the dessert to set and flavors to meld.
When ready to serve, garnish with extra cookie crumbs or a dusting of cocoa powder if desired. Slice and serve chilled.