In a medium bowl, whisk together the gelatin and boiling water until dissolved. Refrigerate until thickened to the consistency of egg whites, about 1 hour.

When the gelatin is thick, whip the evaporated milk in a chilled bowl with chilled beaters until thick enough to form peaks like whipped cream. Fold the whipped milk into the gelatin. Rinse an 8 cup mold and fill with the gelatin mixture. Cover and refrigerate overnight, or at least until set, about 4 hours.

Unmold the gelatin onto a serving dish and sprinkle with cookie crumbs. Put the rest of the crumbs into a bowl and pass around the table at serving time.