Chocolate Hazelnut Truffle Tart

FOR CRUST: Preheat oven to 350 degrees F. Finely grind nuts in food processor (2/3 cup). Add flour and sugar. Pulse to combine. Distribute butter over flour mixture. Pulse until coarse meal forms, about 8 pulses. Add vanilla and pulse until moist clumps form, about 12 long pulses. Gather dough into ball and flatten.

Press dough into 11-inch tart pan with removable bottom to form 1/4-inch-thick crust. Refrigerate 30 minutes. Line with foil and pie weights. Bake until dough is set about 15 minutes. Remove foil and pie weights. Bake until dry and cooked through, about 10 minutes. Cool completely.

FOR FILLING: Place cream and butter in medium saucepan. Bring to simmer over medium heat. Remove from heat. Add chocolate and whisk until smooth. Let cool 15 minutes. Stir in Frangelico. Pour into prepared crust. Chill overnight. Cover when set.

Sift over cocoa powder and garnish with 12 whole hazelnuts.