You can't make authentic tiramisu without using mascarpone. However, I found a way to cut calories and fat without sacrificing taste by substituting nonfat Greek style yogurt for the heavy cream in most recipes. It gives a rich texture, subtle tang and the extra protein is a bonus! I used a round 8 souffle dish but if you use a square pan, you might need a few more ladyfingers. This is very quick to make but you have to be patient with the chilling time. If I make it late in the evening, I am not tempted to eat it until the next day!