In a small bowl, beat cream until stiff peaks form; fold in yogurt. Spread 1/2 cup cream mixture onto bottom of an 8-in. square dish.
In a shallow dish, mix milk and espresso. Quickly dip 12 ladyfingers into espresso mixture, allowing excess to drip off. Arrange in dish in a single layer, breaking to fit as needed. Top with half of the remaining cream mixture; dust with cocoa. Repeat layers.
Refrigerate, covered, at least 2 hours before serving. If desired, serve with raspberries.