Combine the cranberries, 2 tablespoons sugar, and water in a medium saucepan. Bring to a gentle simmer over medium heat.

Cook for 8–10 minutes, stirring occasionally and gently crushing some of the berries as they soften, until the cranberries have burst and the mixture has thickened into a loose, spoonable sauce.

Taste the cranberry sauce and add another tablespoon or two of sugar if you prefer it sweeter. I like keeping it fairly tart because that brightness balances the rich mascarpone filling.

Transfer the cranberry sauce to a bowl and let it cool completely before assembling the tiramisu.

Bring about 1 inch of water to a gentle simmer in a saucepan. Place the egg yolks and 1/4 cup sugar in a heatproof bowl that fits over the saucepan without touching the water.

Whisk the egg yolks and sugar continuously over the gently simmering water until the mixture becomes pale, thick, and creamy, about 8–10 minutes. The mixture should noticeably thicken as it cooks.

Remove the bowl from the heat and continue whisking for another minute or two as the mixture begins to cool.

Let the egg mixture cool slightly, then add the mascarpone and beat until completely smooth and creamy. Avoid overmixing once the mascarpone has been incorporated.

Arrange half of the ladyfingers in a snug, even layer in the bottom of your serving dish.

Lightly brush the ladyfingers with half of the amaretto. You want them moistened and flavored, but not saturated.

Spread half of the mascarpone custard evenly over the ladyfingers.

Spoon half of the cooled cranberry sauce over the mascarpone and gently spread it into an even layer.

Arrange the remaining ladyfingers over the cranberry layer and lightly brush them with the remaining amaretto.

Spread the remaining mascarpone custard over the ladyfingers, smoothing the surface with an offset spatula or the back of a spoon.

Spoon the remaining cranberry sauce over the top. Alternatively, for a more traditional tiramisu appearance, reserve some of the mascarpone mixture for the final layer and use the cranberry sauce between the ladyfingers instead.

Cover and refrigerate for at least 4 hours, although overnight is even better. This gives the ladyfingers time to soften and allows the flavors and layers to come together.

Just before serving, lightly dust with unsweetened cocoa powder, if desired.