Step 1

For syrup, in a small saucepan combine granulated sugar, the water, and espresso powder. Bring to boiling over medium heat, stirring to dissolve sugar. Boil gently, uncovered, 1 minute. Remove from heat. If desired, stir in liqueur.

Step 2

In a chilled large bowl beat cream with chilled beaters of a mixer on medium until soft peaks form (tips curl). In a medium bowlstir together mascarpone cheese and powdered sugar. Fold 1/2 cup of the whipped cream mixture into the mascarpone mixture to lighten. Gently fold the mascarpone mixture into the remaining whipped cream.

Step 3

To assemble, arrange half of the ladyfingers in the bottom of a 9-inch baking pan, cutting to fit as needed. Brush with half of the syrup. Spread with half of the mascarpone mixture and sprinkle with 1 Tbsp. of the cocoa powder. Repeat ladyfinger, syrup, and mascarpone layers.

Step 4

Cover and chill for 4 to 24 hours. Before serving, sift remaining 1 Tbsp. cocoa powder over top.