Rhubarb White Chocolate Elderflower Tart (Print Version)

Crisp tart shell filled with white chocolate elderflower custard and topped with roasted rhubarb for spring celebrations.

# What You Need:

→ Tart Crust

01 - 1.75 cups all-purpose flour
02 - 7 tablespoons cold unsalted butter, cubed
03 - 1/4 cup powdered sugar
04 - 1 large egg yolk
05 - 1-2 tablespoons cold water
06 - Pinch of salt

→ Custard Filling

07 - 5.3 ounces white chocolate, finely chopped
08 - 1 cup heavy cream
09 - 3.4 fluid ounces whole milk
10 - 3.4 fluid ounces elderflower cordial
11 - 3 large egg yolks
12 - 2 tablespoons granulated sugar
13 - 1 teaspoon vanilla extract

→ Rhubarb Topping

14 - 10.6 ounces rhubarb, trimmed and cut into 2-inch batons
15 - 1/4 cup granulated sugar
16 - Zest of 1 lemon
17 - 2 tablespoons elderflower cordial

# Directions:

01 - In a food processor, pulse flour, butter, powdered sugar, and salt until mixture resembles breadcrumbs. Add egg yolk and 1 tablespoon cold water; pulse until dough begins to come together, adding more water as 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 refrigerate for 15 minutes. Preheat oven to 350°F.
03 - Line crust with parchment paper and baking beans. Blind bake for 15 minutes. Remove beans and parchment, then bake for 5-7 minutes more until golden. Cool completely.
04 - In a saucepan, heat cream and milk over medium heat until steaming but not boiling. Remove from heat.
05 - Whisk egg yolks, sugar, and vanilla in a mixing bowl until pale and ribboned. Slowly pour the hot cream mixture into the yolks while whisking constantly to prevent curdling.
06 - Return the mixture to the saucepan over low heat, stirring constantly until slightly thickened and it coats the back of a spoon, approximately 8-10 minutes. Remove from heat.
07 - Add the finely chopped white chocolate and elderflower cordial to the custard. Stir until completely smooth and fully melted.
08 - Pour the custard into the cooled tart shell. Refrigerate for at least 1 hour, until the filling is set and firm to the touch.
09 - Preheat oven to 375°F. Arrange rhubarb batons in a single layer in a baking dish. Sprinkle with sugar and lemon zest, then drizzle with elderflower cordial. Cover with foil.
10 - Roast covered for 15 minutes. Remove foil and roast for 5-8 minutes more until rhubarb is tender but maintains its shape. Cool completely to room temperature.
11 - Arrange the cooled rhubarb batons over the set custard filling. Optionally brush with additional elderflower cordial for a glossy finish. Refrigerate until ready to serve.

# Expert Advice:

01 -
  • It tastes like spring bottled up in pastry, floral and bright without being overly sweet.
  • You can make every component ahead and assemble it the morning of your gathering, which saves your sanity.
  • The contrast between buttery crust, silky custard, and tart rhubarb makes every bite interesting.
  • It looks like something from a bakery window, but it's surprisingly forgiving to make at home.
02 -
  • Do not skip chilling the dough between steps, warm pastry shrinks and loses its shape in the oven.
  • Stir the custard constantly over low heat or you'll end up with sweet scrambled eggs instead of silky filling.
  • Let the rhubarb cool completely before placing it on the custard, hot fruit will melt your beautiful set filling.
  • White chocolate can seize if overheated, so add it off the heat and stir gently until smooth.
03 -
  • Freeze your tart shell for 10 minutes before blind baking to prevent shrinkage and keep those crisp edges intact.
  • Use a fine mesh sieve to strain your custard after cooking if you want an ultra-smooth filling with no bits.
  • Taste your elderflower cordial before using it, some brands are much sweeter than others and you may want to adjust the sugar.
  • Let the tart come to cool room temperature for 10 minutes before slicing so the custard isn't too firm and the flavors open up.
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