Make the pastry using the rubbing-in method. Cover with plastic wrap and place in the fridge for 30 minutes to rest. Meanwhile, to make the filling, place the ricotta in a bowl and use a wooden spoon to beat in the sugar, lemon zest and vanilla until combined. Use a balloon whisk to whisk in the eggs, 1 at a time, until combined. Preheat oven to 180°C. Position an oven rack in the lowest shelf of the oven. Roll out two-thirds of the pastry on a lightly floured surface to a 5mm-thick disc. Line a 3cm deep, 22cm (base measurement) fluted tart tin, with removable base, with pastry and trim excess, leaving a 1cm-wide edge. Fold the edge inside the tin and press to seal. Heat the jam in a small saucepan over medium heat for 1-2 minutes or until melted. Set aside for 3 minutes to cool slightly. Pour the filling into the pastry case. Spoon the jam evenly over the surface. Roll out the remaining pastry on a lightly floured surface to a 5mm-thick disc. Use a ravioli wheel to cut the dough into ten 1.5cm-wide strips. Arrange half the strips, at 2cm intervals, across the top of the tart. Repeat, crossways, with remaining strips. Press the edges to seal and trim any excess. Place the tart on a baking tray. Bake on the middle shelf for 35-40 minutes or until golden. Set aside for 15 minutes to cool in the tin before transferring to a wire rack to cool completely. Dust with icing sugar. Cut into wedges and serve.