1 baked 9” tart shell
400 mL. (1 ¾ cups) pink grapefruit juice
250 g. (1 1/4 cups) sugar, divided
zest of 2 pink grapefruits
1 Tbsp. cornstarch
¼ tsp. salt
6 eggs, divided
115 g. (1/2 cup) cold unsalted butter, cubed
60 mL. (1/4 cup) Lavender syrup
In a small pot on high heat, boil the grapefruit juice until reduced by half.
In a medium pot, combine 200 g (1 cup) sugar and grapefruit zest. Rub them together with your fingertips to release the citrus oils. Whisk in the cornstarch and salt, followed by four eggs and two yolks, and finally the reduced grapefruit juice.
Cook over medium heat, stirring frequently, until mixture comes to a boil. Remove from heat and whisk in butter, a few pieces at a time, until fully incorporated. Pour into tart shell and refrigerate until chilled, at least two hours and up to overnight.
To make the meringue, combine remaining egg whites and sugar with the syrup in the bowl of a standing mixer set over a pot of simmering water, making sure the bowl does not touch the water. Whisk constantly until sugar is dissolved and mixture is warm to the touch. Transfer bowl to standing mixer fitted with the whisk attachment and whip on high speed until white, fluffy and only just warm.
Spread meringue over grapefruit filling. Toast under the broiler for a few minutes or using a torch. This tart is best the day it is made but will keep in the fridge up to three days.