Whisk together ricotta, 1/4 cup confectioners' sugar, 1 tablespoon chocolate, amaretto and orange zest in a medium bowl until well combined.
Stir together brandy, coffee granules and water in a small bowl. Brush over the flat side of the ladyfingers.
Arrange 6 ladyfingers in a row on a serving plate, flat-side up. Spread with 1/3 of the ricotta mixture. Repeat layering twice. Set the remaining 6 ladyfingers on top, rounded-side up. Dust with confectioners' sugar and sprinkle with the remaining chocolate. Loosely cover with plastic wrap and chill for 20 minutes. Cut crosswise into 4 portions.