# What You'll Need:
→ Tart Crust
01 - 1 ¾ cups all-purpose flour
02 - ½ cup cold unsalted butter, cubed
03 - ½ cup powdered sugar
04 - 1 large egg yolk
05 - 1-2 tablespoons cold water
06 - Pinch of salt
→ Custard Filling
07 - 5 oz white chocolate, finely chopped
08 - 1 cup heavy cream
09 - ¼ cup whole milk
10 - ¼ cup elderflower cordial
11 - 3 large egg yolks
12 - 2 tablespoons granulated sugar
13 - 1 teaspoon vanilla extract
→ Rhubarb Topping
14 - 10 oz rhubarb, trimmed and cut into 2-inch batons
15 - ¼ cup granulated sugar
16 - Zest of 1 lemon
17 - 2 tablespoons elderflower cordial
# How to Prepare:
01 - Pulse flour, butter, powdered sugar, and salt in a food processor until mixture resembles breadcrumbs. Add egg yolk and 1 tablespoon cold water; pulse until dough begins to come together, adding more water if needed. Shape into a disk, wrap in plastic, and refrigerate for 30 minutes.
02 - Roll out dough on a floured surface to fit a 9-inch tart tin. Press into tin, trim edges, and chill for 15 minutes.
03 - Preheat oven to 350°F. Line crust with parchment and baking beans; blind bake for 15 minutes. Remove beans and parchment, bake 5-7 minutes more until golden. Cool completely.
04 - In a saucepan, heat cream and milk until steaming but not boiling.
05 - Whisk egg yolks, sugar, and vanilla in a bowl until pale and thickened.
06 - Slowly pour hot cream mixture into yolks while whisking constantly. Return mixture to saucepan over low heat, stirring until slightly thickened and coats the back of a spoon. Remove from heat.
07 - Add white chocolate and elderflower cordial to the warm custard; stir until smooth and fully melted.
08 - Pour custard into cooled tart shell. Refrigerate for at least 1 hour until completely set.
09 - Preheat oven to 375°F. Arrange rhubarb batons in a single layer in a baking dish. Sprinkle with sugar, lemon zest, and drizzle with elderflower cordial. Cover with foil and roast for 15 minutes. Remove foil and roast 5-8 minutes more until tender but not falling apart. Cool completely.
10 - Arrange cooled rhubarb over set custard in an attractive pattern. Optionally brush with extra elderflower cordial for shine. Refrigerate until ready to serve.
