Rhubarb White Chocolate Elderflower Tart

The smell of elderflower always takes me straight back to late May mornings, when the hedgerows near my flat bloomed with those creamy white clusters. I'd started making this tart on a whim one Saturday after I impulse-bought a bottle of elderflower cordial and a bundle of bright pink rhubarb at the farmers market. The combination sounded fancy, maybe even a little risky, but I figured white chocolate would soften the sharpness. When I pulled it from the fridge that evening, the custard had set like silk, and the rhubarb glistened on top like stained glass.

I made this tart for my sisters birthday dinner last spring, and she still talks about it. She's not usually one for desserts with fruit, but the way the tangy rhubarb cut through the creamy custard won her over completely. I remember her scraping her plate with the side of her fork, trying to get every last bit of that elderflower custard. That's when I knew this recipe was a keeper.

Ingredients

• All-purpose flour: Forms the base of a tender, crumbly tart crust that holds its shape beautifully after baking.
• Cold unsalted butter, cubed: Cold butter is key for flakiness, work quickly so it doesnt melt before baking.
• Powdered sugar: Dissolves easily into the dough and gives the crust a delicate sweetness without graininess.
• Egg yolk: Adds richness and helps bind the dough together without making it tough.
• Cold water: Use just enough to bring the dough together, too much makes it sticky and hard to roll.
• Salt: A small pinch balances the sweetness and enhances all the other flavors.
• White chocolate, finely chopped: Choose good quality white chocolate with cocoa butter listed first, it melts smoother and tastes less waxy.
• Heavy cream: Creates the luscious, creamy body of the custard filling.
• Whole milk: Thins the custard slightly so it pours easily and sets without being too dense.
• Elderflower cordial: This is the magic ingredient, it brings a subtle floral sweetness that makes the whole tart sing.
• Egg yolks: Thicken the custard and give it that rich, velvety texture.
• Granulated sugar: Sweetens the custard and the rhubarb topping just enough without overpowering the floral notes.
• Vanilla extract: Adds warmth and depth to the custard, rounding out the flavor.
• Rhubarb, trimmed and cut into batons: Look for firm, bright stalks, they roast up tender but hold their shape perfectly.
• Lemon zest: Brightens the rhubarb and keeps it from tasting flat or one-dimensional.

Instructions

Mix the tart dough:

Pulse the flour, cold butter, powdered sugar, and salt in a food processor until it looks like coarse sand. Add the egg yolk and a tablespoon of cold water, then pulse just until the dough starts to clump together, if its still too dry, add another splash of water.

Chill and roll the crust:

Pat the dough into a flat disk, wrap it tightly in plastic, and refrigerate for 30 minutes. Roll it out on a floured surface until its large enough to line your tart tin, then press it in gently, trim the edges, and chill again for 15 minutes.

Blind bake the shell:

Preheat your oven to 180°C, line the chilled crust with parchment paper, fill it with baking beans, and bake for 15 minutes. Remove the beans and parchment, then bake for another 5 to 7 minutes until the crust is golden and crisp.

Prepare the custard base:

Heat the cream and milk in a saucepan until steaming but not boiling. In a separate bowl, whisk the egg yolks, sugar, and vanilla until pale and slightly thickened.

Cook the custard:

Slowly pour the hot cream mixture into the yolks, whisking constantly so the eggs dont scramble. Return everything to the saucepan and cook over low heat, stirring gently, until the custard thickens enough to coat the back of a spoon.

Finish the custard:

Take the pan off the heat, stir in the chopped white chocolate and elderflower cordial until completely smooth and glossy. Pour the custard into your cooled tart shell and refrigerate for at least an hour until fully set.

Roast the rhubarb:

Heat the oven to 190°C, lay the rhubarb batons in a single layer in a baking dish, and sprinkle with sugar, lemon zest, and elderflower cordial. Cover with foil and roast for 15 minutes, then uncover and roast another 5 to 8 minutes until tender but still holding their shape.

Assemble and chill:

Once the rhubarb has cooled completely, arrange the batons on top of the set custard in whatever pattern makes you happy. If you want extra shine, brush them lightly with a bit more elderflower cordial, then chill until youre ready to serve.

Save

One evening I served this tart after a long Sunday roast, and my friend Tom, who claimed he didnt like rhubarb, had two slices. He said the elderflower made it taste like spring itself, which is probably the nicest compliment Ive ever gotten for a dessert. Now I make it every year when the rhubarb comes back, and it feels like a little ritual that marks the season.

Make-Ahead Magic

This tart is a lifesaver when youre hosting because every single part can be done in advance. I usually bake the shell the day before, make the custard the morning of, and roast the rhubarb a few hours ahead. You can even assemble the whole thing and keep it chilled for up to six hours before serving. Just pull it out about ten minutes before you slice it so the custard softens slightly, it tastes even better when its not ice cold.

Flavor Swaps and Tweaks

If you cant find elderflower cordial, you can use a splash of orange blossom water or even a light honey syrup, though youll lose that signature floral note. I've also tried this with roasted strawberries when rhubarb wasnt in season, and it was lovely, just a bit sweeter and less tart. Some people like to fold in a handful of toasted pistachios or almonds for crunch, and honestly, I wont stop you.

Serving and Pairing Ideas

This tart is rich enough to stand on its own, but a small dollop of unsweetened whipped cream or creme fraiche cuts through the sweetness beautifully. I love serving it with a glass of chilled Moscato or even a homemade elderflower spritz, the floral notes echo each other in the best way. If youre feeling fancy, dust the edges with a tiny bit of powdered sugar just before bringing it to the table.

• Slice with a sharp knife dipped in hot water for clean edges.
• Store leftovers covered in the fridge for up to two days, though the crust softens slightly.
• Let the tart sit at room temperature for 10 minutes before serving for the best texture.

Save

This tart has become my go-to when I want to impress without spending all day in the kitchen. Theres something about the combination of creamy, floral, and tart that just works, and every time I make it, someone asks for the recipe.

Recipe FAQs

→ Can I make this tart ahead of time?

Yes, this is an ideal make-ahead dessert. Prepare the tart shell and custard up to a day in advance, then add the roasted rhubarb a few hours before serving for best presentation.

→ What can I substitute for elderflower cordial?

If elderflower cordial is unavailable, use a light honey syrup with a splash of lemon juice, or try rose water for a different floral note. Adjust sweetness to taste.

→ How do I prevent the rhubarb from becoming mushy?

Cut rhubarb into even batons and roast covered initially to cook through, then uncover briefly to caramelize. Remove from oven when tender but still holding shape, and cool completely before arranging on the tart.

→ Can I use frozen rhubarb?

Fresh rhubarb works best for maintaining shape and texture. If using frozen, thaw completely and pat dry before roasting to remove excess moisture that could make the topping watery.

→ What type of white chocolate should I use?

Choose high-quality white chocolate with at least 30% cocoa butter for the smoothest, creamiest custard. Avoid white baking chips as they often contain stabilizers that prevent proper melting.

→ How should I store leftover tart?

Cover loosely with plastic wrap and refrigerate for up to 2 days. The rhubarb may release some juice over time, so it's best enjoyed within 24 hours for optimal texture and appearance.