Serves: 1 (28-cm) tart
1) Blend the flour, corn flour, 120g pine nuts, 50g sugar, and salt in a food processor until finely ground. Add the butter and pulse, just until the dough forms. Press the dough over the bottom and about 4-cm up the sides of an 22-cm diameter tart pan with a removable bottom. Refrigerate until the dough is firm, about 30 minutes.
2) Preheat the oven to 180°C/ gas mark 4.
3) Line the tart dough with aluminum foil and fill with pie weights or dried beans. Bake the tart case in the lower third of the oven until just set, about 25 minutes. Carefully remove the foil and pie weights. Bake the case until golden, about 10 minutes longer. Cool completely.
4) Combine the remaining 150g of sugar with 115ml water in a small saucepan. Bring to a boil, stirring until the sugar dissolves. Cool the sugar syrup slightly.
5) Melt the chocolate in a heatproof bowl over pan very softly simmering water.
6) Pulse the ricotta cheese and cream cheese in a food processor until smooth. Add the egg and egg yolks, one at a time, and process until smooth. Add the melted chocolate and process until combined. With the machine running, add the sugar syrup in a thin steady stream and process until smooth.
7) Pour the custard into the tart shell and bake until the filling is almost set, about 30 minutes or until the custard has set. Scatter the remaining 120g toasted pine nuts on top of the filling. Let the tart cool completely before serving.
8) The tart can be wrapped in plastic and refrigerated for up to 3 days. Return the tart to room temperature before serving.