In a clean dry bowl, whisk the egg whites and salt until they form stiff peaks. Add the sugar, a spoonful at a time until it is all incorporated.
Line a tray with baking parchment and draw out even circles. Spread the meringue into the circles on the tray and cook for 2 hours at 100°C.
Remove from the oven and leave to cool.
Start with a base layer of meringue, then spread a layer of grapefruit curd followed by a thick layer of whipped cream. Repeat to desired height and top with a layer of meringue.
Serve with the ice cream on the side.
Place the egg yolks, sugar, butter, and grapefruit juice in a bowl. Place the bowl over a saucepan of simmering water and whisk occasionally until the curd has thickened. Remove from the heat and allow to cool completely.