Rhubarb White Chocolate Elderflower Tart

Spring hit hard one April when our neighbor dropped off a bundle of ruby-red rhubarb stalks still cold from her garden. I had white chocolate left over from Easter and a bottle of elderflower cordial I'd been hoarding since summer. The tart that emerged from that improvised afternoon became the dessert I now make whenever I want to look like I planned ahead. It's showy but forgiving, and the floral notes make everything taste like sunshine even when the weather hasn't quite caught up.

I served this at a garden party where half the guests were gluten-free and the other half were chocolate snobs. The tart won over both camps, mostly because the rhubarb looked so dramatic fanned across the top. Someone asked if I'd trained at a pastry school. I didn't admit I'd learned to blind bake from a YouTube video at midnight three years prior.

Ingredients

• All-purpose flour: The base of your tart shell, and using cold butter with it creates those flaky, crumbly layers you want in a proper crust.
• Cold unsalted butter, cubed: Keep it refrigerator-cold so it doesn't melt into the flour before baking, which is what gives you that tender, crisp texture.
• Powdered sugar: Sweetens the crust without adding graininess, and it also helps the dough stay soft and easy to roll.
• Egg yolk: Binds the dough and adds richness without making it tough like a whole egg might.
• Cold water: Just enough to bring the dough together, add it slowly so you don't end up with a sticky mess.
• Salt: A pinch wakes up the butter flavor and keeps the crust from tasting flat.
• White chocolate, finely chopped: The star of the custard, melting into silky sweetness that balances the tart rhubarb beautifully.
• Heavy cream: Makes the custard luscious and thick, the kind that clings to your spoon in the best way.
• Whole milk: Thins the cream just enough so the custard isn't overwhelmingly rich.
• Elderflower cordial: Adds that haunting floral note that makes people ask what the secret ingredient is.
• Egg yolks: Thicken and enrich the custard, turning it glossy and golden as it cooks.
• Granulated sugar: Sweetens both the custard and the rhubarb, though the rhubarb needs more to tame its sour edge.
• Vanilla extract: A background hum of warmth that rounds out the white chocolate without competing.
• Rhubarb, trimmed and cut into batons: The tart, pink beauty that makes this dessert look like it belongs in a bakery window.
• Lemon zest: Brightens the rhubarb and keeps it from tasting one-note sweet.

Instructions

Make the Tart Crust:

Pulse the flour, cold butter, powdered sugar, and salt in a food processor until it looks like coarse sand, then add the egg yolk and water just until the dough clumps together. Wrap it in plastic, chill it for thirty minutes, then roll it out and press it into your tart tin, chilling again before you blind bake it with parchment and beans until golden.

Prepare the Custard Filling:

Heat the cream and milk until steaming, then whisk it slowly into your beaten egg yolks and sugar so they don't scramble. Cook the mixture gently on the stove until it thickens enough to coat a spoon, then stir in the white chocolate and elderflower cordial until glossy and smooth.

Roast the Rhubarb:

Lay the rhubarb batons in a baking dish, sprinkle with sugar and lemon zest, drizzle with elderflower cordial, then cover and roast until tender but still holding their shape. Let them cool completely so they don't melt the custard when you arrange them on top.

Assemble and Chill:

Pour the custard into the cooled tart shell and refrigerate for at least an hour until set. Arrange the roasted rhubarb over the custard, brush with a little extra cordial if you want shine, then chill until you're ready to slice and serve.

Save

The first time I brought this tart to a potluck, someone sliced into it before I arrived and I walked in to find perfect wedges already plated. That's when I knew it had become a real recipe, the kind that doesn't need me hovering nearby to explain it. It just sits there looking beautiful and tasting like spring decided to show up in pastry form.

Making It Ahead

The tart shell can be baked up to two days in advance and kept in an airtight container at room temperature. The rhubarb roasts beautifully a day ahead and holds in the fridge without losing its shape. I usually make the custard the morning of, pour it into the shell, let it set, then top with rhubarb an hour before serving so everything tastes fresh but I'm not sweating in the kitchen while guests arrive.

Substitutions and Swaps

If you can't find elderflower cordial, a tablespoon of honey mixed with a squeeze of lemon and a drop of rose water gets you close. Strawberries work in place of rhubarb, though you lose that tart punch that makes the dessert so balanced. For a gluten-free crust, swap in a good quality gluten-free flour blend and add an extra tablespoon of butter to keep it from crumbling apart when you roll it out.

Serving Suggestions

This tart begs to be served cold with nothing more than a dusting of powdered sugar, though a dollop of lightly whipped cream never hurt anyone. A glass of chilled Moscato or an elderflower spritz echoes the floral notes without overwhelming them. If you want texture, scatter toasted pistachios or slivered almonds over the rhubarb just before serving.

• Slice with a sharp knife dipped in hot water for clean edges.
• Let the tart sit at room temperature for ten minutes before serving so the custard softens just slightly.
• Leftover slices keep in the fridge for up to three days, though the crust softens a bit as it sits.

Save

Every time I make this tart, I'm reminded that the best desserts don't need to be complicated, they just need to taste like you cared. This one does that without breaking a sweat.

Questions & Answers for Recipes

→ Can I make this tart in advance?

Yes, this is an excellent make-ahead dessert. The tart shell and custard can be prepared up to 2 days ahead. Add the roasted rhubarb within a few hours of serving to maintain its texture and appearance.

→ What can I substitute for elderflower cordial?

You can use elderflower liqueur for a more intense flavor, or substitute with orange blossom water, rose water, or a vanilla simple syrup. Each will provide a unique floral or aromatic note to the custard.

→ How do I prevent the tart crust from becoming soggy?

Blind baking the crust completely until golden is essential. Additionally, ensure the custard is fully cooled before pouring it into the shell, and only add the rhubarb topping shortly before serving to maintain crispness.

→ Can I use frozen rhubarb instead of fresh?

Fresh rhubarb is recommended for the best texture and appearance. If using frozen, thaw completely and drain excess liquid before roasting. Frozen rhubarb may become softer and release more moisture during cooking.

→ What type of white chocolate works best?

Choose high-quality white chocolate with at least 30% cocoa butter for the smoothest, most flavorful custard. Avoid white chocolate chips, as they contain stabilizers that prevent proper melting and may create a grainy texture.

→ How should I store leftover tart?

Store covered in the refrigerator for up to 3 days. The rhubarb may release some juice over time, so it's best enjoyed within the first 24 hours for optimal presentation and texture.