Combine flour and sugar in a bowl. Cut butter in with a pastry blender til texture of coarse crumbs.

Combine ice water and vanilla. Drizzle over flour mixture. Stir with a fork until dough starts to form a ball. Work gently with your hands till you can form a ball. Wrap and refrigerate approx 15 minutes.

Roll out on a lightly floured parchment paper to fit a 10 inch spring pan. Press it into the pan working the dough about an inch up the sides. Prick the base with a fork and refrigerate 30 minutes more.

Preheat oven to 375 degrees while dough cools.

Toast the walnuts on the baking sheet for about 8 minutes until fragrant. Let cool and finely chop.

After dough has rested for the 30 minutes as per above, line the tart shell with parchment and weight the dough down with pie weights.

Place a baking sheet on the lowest rack to shield the tart shell which you will bake on the middle rack for about 20 minutes til edge is dry. Remove the pie weights and parchment paper and bake a further 10-15 minutes until until just starting to take on golden colour and it is firm.

Remove the tart shell from the oven and let cool. Reduce the oven to 325 degrees and leave the bottom baking sheet in place.

Whisk eggs, maple syrup, sugar, butter and vanilla in a medium bowl until well blended.

Spread the raisins evenly in the bottom of the cooled tart shell. Pour the filling in the tart shell over the raisins.

Bake for about 35 minutes until filling has risen around the edge and is just set in the center. Let cool completely.

Sprinkle gelatin over 2 tablespoon of the cream and let soften about 5 minutes.

Measure out ¼ cup of the remaining cream and put what is left in a mixing bowl in the fridge to stay cool.

Whisk egg yolks in a small bowl till well blended. Bring maple syrup to boil in small saucepan over med-high heat. Boil about 3 minutes being careful that it doesn't boil over. Syrup should be fragrant and slightly darker. Remove from the heat and allow bubbling to subside and pour in the ¼ cup of cream.

Gradually pour the syrup into the egg yolks whisking constantly. Be careful not to cook the egg yolks. Return the mix to the sauce pan and return to cook of med-low heat until mixture starts to thicken. Whisking constantly, this should take about 3 minutes.

Stir in gelatin and cook for about 2 minutes until gelatin is dissolved.

Transfer to a clean bowl and let cool, stirring often for about 15 minutes.

Meanwhile, whip the remaining cream in the chilled bowl until it forms soft peaks. Fold in vanilla. Stir one quarter of the cream into the cooled egg yolk/gelatin mixture until well blended. Then add this back into the cream in the mixing bowl. Beat again until well blended.

Fold in walnut pieces if using. Spread over the tart and refrigerate at least 30 minutes or up to 8 hours.

Remove ring from the tart pan, transfer to a plate and serve.