10rhubarb stalks, trimmed and cut into 3cm pieces2 tbspcaster sugar½orange, juice only80 gmmascarpone50 gmunsalted butter, coarsely chopped75 gm (½ cup)plain flour60 gmrolled oats90 gmamaretti biscuits, coarsely crushed55 gm (¼ cup)demerara sugarTo serve:pistachio gelato (see note)
Preheat oven to 180C. Combine rhubarb, caster sugar and orange juice in a saucepan over low heat, stirring to dissolve sugar. Increase heat to medium, cover and simmer until rhubarb is just tender (4-5 minutes). Cool, stir in mascarpone and spoon into a 6cm deep, 14cm x 19cm ovenproof dish. Set aside.
In a bowl, rub butter into flour with your fingertips to form fine crumbs. Stir in oats, amaretti and demerara sugar, mix well, spread in an even layer on a baking paper-lined oven tray and bake until just dry (8-10 minutes). Scatter over rhubarb mixture and bake until golden (20-25 minutes). Cool slightly and serve with pistachio gelato and Pimped Fizz.
Note Pistachio ice-cream is available from fine food stores and gelaterie.