Process pistachios to fine crumbs. Add flour and icing sugar and process to combine. Add butter and pulse until mixture resembles breadcrumbs. Gradually add enough water until dough just comes together. Shape into a disc, wrap and refrigerate for 30 minutes

Lightly grease a 23cm round 4cm deep tart pan with removable base. Roll out dough on a lightly floured surface to a 4mm thick round. Line pan with pastry and trim edges. Refrigerate for 30 minutes

Preheat oven to 180C. Blind bake pastry case for 20 minutes. Then bake uncovered for 15 minutes, until golden and crisp. Cool

To make the custard, place milk and vanilla bean paste in a saucepan and bring almost to boiling point. In a large bowl, whisk egg yolks and sugar until pale and thick. Whisk in flours. Gradually whisk in warm milk mixture. Return to saucepan. Cook over medium heat, stirring constantly, until custard boils and thickens. Simmer, stirring, for 2 minutes

Pour into pastry case and smooth surface. Chill for 2 hours or until cold and firm to the touch

To make the rose jelly, process raspberries, sugar and water together until smooth. Strain through a fine sieve

Sprinkle gelatine over 2 tbsp of just boiled water, whisking with a fork to dissolve. Whisk into raspberry mixture with rosewater. Pour over custard layer and chill for 2 hours, or until set firm

Decorate top of tart with extra chopped pistachios and rose petals