In a medium bowl, brew strong coffee and add coffee liqueur if using. Set aside to cool.
In a large mixing bowl, beat mascarpone cheese until smooth.
In a separate bowl, whip heavy cream with powdered sugar and vanilla until stiff peaks form.
Gently fold whipped cream mixture into mascarpone until well combined.
Slice each eclair horizontally into two pieces.
Quickly dip the bottom half of each eclair into the coffee mixture, about 2 seconds per side.
Arrange dipped eclair bottoms in a 9x13 inch dish.
Spread half of the mascarpone mixture evenly over the eclair layer.
Dust lightly with cocoa powder.
Dip the remaining eclair tops in coffee mixture and place on top of the first layer.
Cover with remaining mascarpone mixture.
Dust generously with cocoa powder and sprinkle with grated chocolate.
Cover and refrigerate for at least 4 hours or overnight before serving.Retry
