Tiramisù Cups

Preparation

1. Step 1

   Set aside 5 ladyfingers; break the remainder into large pieces. To assemble, dip the pieces in the coffee; fit a layer into the bottom of each cup. Cover each with 1/4 cup mascarpone filling. Top with another layer of ladyfingers dipped in coffee; cover with 1/4 cup mocha filling. Garnish each with a dollop of mascarpone filling, half a reserved ladyfinger, and a sprinkling of espresso.

2. Mascarpone Filling

   Step 2

   In the heatproof bowl of an electric mixer, combine the egg, egg yolks, 1/2 cup sugar, and vanilla. Place over a pan of simmering water; whisk until the sugar is dissolved, about 3 minutes. Transfer the bowl to the mixer; using the whisk attachment, beat on medium-high speed until the mixture is cool, about 5 minutes. Add the mascarpone; beat on low speed to combine. Set aside.

   Step 3

   Place the egg whites in another heatproof mixing bowl set over a pan of simmering water. Add the remaining 1/2 cup sugar; whisk until it is dissolved, about 2 minutes. Transfer the bowl to the mixer; using the whisk attachment, beat on medium speed until soft peaks form, about 5 minutes. Fold one-third of the egg whites into the mascarpone mixture; fold in the remaining whites. Refrigerate, covered, until ready to use, up to 1 day.

3. Mocha Filling

   Step 4

   Prepare an ice-water bath; set aside. In a large heatproof bowl set over a pan of simmering water, combine the sugar, cornstarch, and salt. Add the chocolate, half-and-half, egg yolks, and egg; whisk until the chocolate is melted, about 3 minutes. Slowly add the coffee, whisking constantly.

   Step 5

   Cook, stirring with a wooden spoon, until the mixture is thick enough to coat the back of the spoon, 2 to 3 minutes. Remove from heat; stir in the butter. Place the bowl in the ice bath; stir occasionally until the mixture is cool. Store in an airtight container at room temperature up to 1 day.