Mascarpone is a sinfully rich double or triple cream cheese that originated in the Lombardy region of Italy. It has a delicate, buttery flavor with just a hint of sweetness. Look for it in the cheese case in large supermarkets, specialty cheese shops or gourmet food stores.
*1/8 teaspoon rum extract mixed with 2 tablespoons water can be substituted for the rum.
**2 packages frozen (thawed) pound cake (10.75-oz each) can be substituted for the ladyfingers. Place each pound cake on its side; carefully cut each into 3 lengthwise slices (to total 6 slices). Brush each slice with espresso mixture (do not soak). Arrange 3 slices crosswise in baking dish. Layer as directed in step 4, adding remaining 3 slices.