90 gmbutter, coarsely chopped130 gmpure icing sugar, sieved70 gmpistachios, roasted, peeled and cooled2oranges, finely grated rind only (reserve juice for candied orange rind)35 gm(¼ cup) plain flour3eggwhites, lightly beaten2 tsporange blossom waterOrange vanilla pastry100 gmbutter, softened100 gmpure icing sugar, sieved1orange, finely grated rind only1vanilla bean, scraped seeds only2eggs250 gm(1 2/3 cups) plain flourCandied orange rindRind of 1 orange, removed with a peeler, thinly sliced130 gmcaster sugar3oranges, juice only2 tsporange blossom water
For orange vanilla pastry, beat butter, icing sugar, orange rind and vanilla seeds in an electric mixer until pale and creamy (2-3 minutes). Add eggs one at a time, beating well and scraping down sides of bowl after each addition. Add flour and a pinch of salt, beat until just combined, then turn onto a lightly floured surface and form into a disc. Wrap in plastic wrap and refrigerate until firm (1½-2 hours). Roll out pastry on a lightly floured surface to 2mm thick and use to line 24 petits four-size tartlet tins (some pastry may be left over). Refrigerate for 30 minutes.
Meanwhile, for candied orange rind, place rind in a small saucepan of cold water, bring to the boil, drain and repeat twice. Combine sugar, two thirds of the orange juice and 60ml water in a small saucepan. Stir over medium heat to dissolve sugar and bring to a simmer. Add blanched orange rind, bring to the boil, reduce heat to low and simmer, brushing down sides of pan with a wet pastry brush to remove sugar crystals. Cook until rind is translucent (8-10 minutes). Remove from heat, stir in orange blossom water and remaining orange juice and set aside.
Preheat oven to 200C. Cook butter in a small saucepan over medium-high heat until dark nut brown (3-4 minutes), remove from heat and cool completely.
Process icing sugar and pistachios in a food processor until finely ground. Transfer to a bowl, add orange rind and flour and stir to combine. Whisk in eggwhites, then cooled butter and orange blossom water. Spoon into prepared tartlet tins and bake on an oven tray until golden and risen (8-10 minutes). Cool on a wire rack and serve topped with candied orange rind and a little orange syrup.