A creamy, nutty dessert with crunchy hazelnuts and espresso-infused cream.
For the tart:
Combine the mascarpone, hazelnut paste, sugar and rum in the bowl of a mixer and beat until smooth. In a separate bowl, whisk the heavy cream until soft peaks form. Fold the whipped cream into the mascarpone-hazelnut mixture. Place the mixture the in the tart shell and smooth the top. Refrigerate at least ½ hour to firm.
For the chocolate glaze:
Heat the cream and butter in a saucepan until the butter melts and the cream begins to simmer. Pour the hot liquid over the chocolate and stir until the mixture is smooth and the chocolate is melted. Pour the glaze over the top of the tart shell and sprinkle with the chopped hazelnuts. Refrigerate again to set the chocolate.
For the espresso cream:
Combine the cream, espresso powder and sugar in a small saucepan. Heat the mixture until the espresso powder and sugar are dissolved. Place the cream over an ice bath and chill completely. Whip the cream to soft peaks. Refrigerate until tart is served. Serve each tart topped with a spoonful of the espresso cream.