Add all ingredients except butter to a saucepan.
Whisk while the curd thickens over medium low heat .
Strain the curd into a bowl.
Whisk in one piece of butter at a time.
To make the meringue, whisk and heat the egg whites and sugar in a double boiler.
Add the heated egg white mixture to the stand mixer bowl.
Add cornstarch to the meringue at soft peak stage.
Whip until stiff peaks form.
Trace six, 4-inch rounds onto parchment paper.
Work the meringue down and around into nests, then bake.
Pour the grapefruit curd into the baked mini pavlova nests.
Segment a grapefruit for garnish.