Preheat the oven to 220°C.
Sift icing sugar, flour, baking powder, and salt into a large bowl.
Add milk and melted butter to the dry ingredients and knead into a dough.
Roll the dough to a thickness of 3cm on a floured surface.
Cut out 5cm wide rounds and place them on a greased baking tray.
Bake for 8 to 10 minutes until the scones are golden.
Combine eggs, passion fruit, and caster sugar in a bowl over simmering water.
Stir the mixture continuously for 8 minutes until it thickens.
Remove from heat and whisk in the softened butter.
Cool the curd and serve with warm scones and whipped cream.