Tiramisu Mousse Recipe

Brew 1 cup of very strong espresso or coffee. While still hot, stir together the coffee and 1/4 cup granulated sugar in a small saucepan and heat over medium until the sugar dissolves and the mixture is just simmering (about 2–3 minutes). Remove from heat and let cool to room temperature.

Once cooled, stir in 2 tablespoons dark rum or coffee liqueur if using. Transfer the syrup to a shallow dish for dipping ladyfingers.

Prepare a zabaglione

Set a heatproof bowl over a saucepan of gently simmering water (bain-marie), making sure the bowl's bottom does not touch the water. Whisk together 4 egg yolks and 1/2 cup granulated sugar until combined. Place the bowl over the simmering water and whisk constantly for about 6–8 minutes, until the mixture is pale, thickened, and reaches about 160°F (safe for eggs). Remove from heat and whisk for 1 minute to cool slightly.

Allow the zabaglione to cool to warm (not hot). Fold in the 16 oz mascarpone cheese in three additions, gently whisking or folding until smooth and homogenous. Add 1 teaspoon vanilla extract and fold to combine. Chill the mascarpone mixture briefly (10 minutes) if it becomes too loose to hold shape.

Whip cream and combine

In a chilled mixing bowl, pour 1.5 cups cold heavy cream and add 2 tablespoons granulated sugar. Whip on medium-high speed to medium-stiff peaks (be careful not to overwhip). Reserve about 1/4 cup whipped cream for topping if you like extra decoration.

Gently fold 3/4 of the whipped cream into the mascarpone-zabaglione mixture in two additions, using a rubber spatula and folding motion to keep the mousse light and airy. Stop when the mixture is smooth and uniform; fold in the remaining whipped cream if you want a lighter texture or keep a small amount aside for decoration.

Quickly dip each ladyfinger into the cooled coffee syrup for 1–2 seconds (do not soak; they should be moist but not falling apart). Arrange a single layer of dipped ladyfingers in the bottom of a 9-inch (23 cm) springform pan, 8x8-inch pan, or a similarly sized serving dish.

Spread about half of the mascarpone mousse evenly over the ladyfinger layer, smoothing the top with an offset spatula. Arrange a second layer of dipped ladyfingers over the mousse (trim cookies to fit if necessary).

Top the second ladyfinger layer with the remaining mascarpone mousse and smooth the surface. If reserved whipped cream is available, pipe or dot it around the top edge for decoration.

Cover the assembled tiramisu with plastic wrap and refrigerate at least 6 hours, preferably overnight, to allow flavors to meld and the mousse to set.

Before serving, dust the top generously with 2 teaspoons unsweetened cocoa powder and sprinkle 1 tablespoon finely grated dark chocolate, if using. Release from the springform pan or slice directly in the serving dish and serve chilled.