For rhubarb ice-cream, simmer rhubarb, 100gm sugar and lemon juice in a saucepan over medium heat, stirring occasionally, until sugar dissolves and rhubarb breaks down (10 minutes). Cool, purée with a hand-held blender, press through a fine sieve (discard solids) and refrigerate until required. Whisk yolks, vanilla seeds and remaining sugar in a bowl until pale. Bring milk to the boil in a saucepan over medium-high heat, then, whisking continuously, gradually pour onto egg mixture. Return mixture to pan and stir continuously over low-medium heat until mixture coats the back of a spoon or reaches 85C (6-7 minutes). Stir in pouring cream, then pass through a fine sieve and refrigerate to cool. Stir in rhubarb purée, then churn in an ice-cream machine and freeze until required.
For sweet shortcrust pastry, stir sugar, vinegar and 110ml water in a bowl until dissolved. Mix flour and ½ tsp fine salt in a large bowl then scatter with butter. Rub butter into flour with your fingertips to partly combine. Turn out onto a work surface, sprinkle with sugar mixture and use your palm to “smear” mixture away from you. Scrape back and repeat smearing process twice, then bring pastry into a ball and flatten to form a disc. Wrap in plastic and refrigerate to rest (2 hours or overnight).
Roll out pastry to 3mm thick, place in a 28cm-diameter, 2.5cm-deep loose-bottom fluted tart tin, pressing sides and trimming edges. Place in freezer for 20 minutes to rest.
Preheat oven to 200C. Blind bake pastry case (15-20 minutes), then remove paper and weights and bake until golden (15-20 minutes). Set aside to cool on a wire rack.
Reduce oven to 120C. Whisk cream, milk, yolks, sugar and vanilla seeds in a large bowl to combine, strain through a fine sieve and spoon off any froth on surface. Pour into tart shell and bake for 30 minutes, then dust with nutmeg and bake until just set (30-40 minutes). Set aside to cool, then serve at room temperature with rhubarb ice-cream. Tart is best served on the day it’s made.
This recipe is from the April 2013 issue of Australian Gourmet Traveller.