1.To make strawberry sauce, place 300g strawberries and 100g caster sugar in a saucepan over medium heat; bring to a simmer. Stir to dissolve sugar and cook 5-10 minutes or until strawberries are soft and sauce is shiny. Use a stick blender to puree until smooth.
2.To make zabaglione, place egg yolks, remaining caster sugar, rose and reduced cranberry juice in a large heatproof bowl and whisk by hand until combined. Place bowl over a saucepan of simmering water (base of bowl should not touch water) and whisk rapidly for 10 minutes until syrup is thick enough to coat the back of a spoon. Remove from heat and beat at high speed with an electric mixer until cool. Refrigerate at least 2 hours or overnight.
3.Preheat oven to 220°C (200°C fan). Lay rhubarb on a baking tray and dust with icing sugar. Bake 10 minutes, then remove from oven to cool completely.
4.Whisk cream to firm peaks. Fold cream through zabaglione, a third at a time, until smooth. Spoon strawberry sauce in the base of serving glasses or bowls. Cut remaining strawberries into quarters. Spoon zabaglione over sauce and arrange rhubarb and fresh strawberries on top.