Flaky, all-butter golden pastry filled with a delicately spiced sweet filling, baked until crisp and aromatic.
Boil 1 1/2 cups of the sugar with 1 cup of the water and the cream of tartar to 115C.
Whisk the cornflour with the remaining water into a perfectly smooth slurry.
Whisking constantly, slowly add the hot syrup to the starch slurry in a heavy pan.
Simmer, stirring without stopping, until the mixture is thick, glassy, and pulls away from the pan, about 1 hour.
Off the heat, stir in the rose water and the pistachios.
Pour into an oiled tin, smooth the top, and rest uncovered overnight.
Cut into cubes with an oiled knife and toss each piece in icing sugar.