Rhubarb White Chocolate Elderflower Tart

The first time I encountered elderflower was at a garden party in Oxford, where an elderly neighbor pressed a glass of homemade cordial into my hands and watched my face light up at the impossibly delicate flavor. Years later, when I found myself staring at forced rhubarb at the market, that memory came flooding back and I knew exactly what had to happen. The combination of tart ruby stalks and floral sweetness has become my absolute favorite way to welcome spring, and this tart never fails to make people pause mid-bite and ask what that secret ingredient is.

I served this at my mothers birthday dinner last spring, and my aunt who claims to dislike desserts that are too sweet actually went back for seconds. The way the roasted rhubarb glistens on top of that pale cream filling makes it look like something from a bakery window, but truthfully the most satisfying part is how quiet the table gets when everyone takes that first bite together.

Ingredients

• 200 g all-purpose flour: Ive learned that weighing flour instead of measuring by cup makes all the difference in tart shells, preventing that dreaded soggy bottom situation
• 100 g cold unsalted butter: Keep this ice cold and work quickly, those visible bits of butter in the dough are what creates flaky layers
• 50 g powdered sugar: Dissolves more easily than granulated sugar and gives the crust a tender, shortbread like texture
• 1 large egg yolk: The richness helps the crust hold together without becoming tough
• 1-2 tbsp cold water: Add this sparingly, just enough to bring the dough together, you want to see bits of butter still visible
• Pinch of salt: Even sweet pastry needs salt to balance flavors and enhance that buttery taste
• 150 g white chocolate: Use a good quality bar with at least 30% cocoa butter, cheap white chocolate can seize and ruin your custard
• 250 ml heavy cream: The high fat content is essential for that luxurious, silky custard texture
• 50 ml whole milk: Lightens the mixture slightly so the filling isnt overwhelmingly rich
• 60 ml elderflower cordial: This is the star, look for one without artificial colors if possible, the floral flavor is delicate but unmistakable
• 3 large egg yolks: Room temperature yolks incorporate more smoothly into the hot cream mixture
• 30 g granulated sugar: Just enough to sweeten the custard without competing with the white chocolate
• 1 tsp vanilla extract: Pure extract makes a noticeable difference here
• 300 g rhubarb: Forced rhubarb with its shocking pink color creates the most beautiful presentation
• 60 g granulated sugar: Rhubarb needs this sweetness to tame its natural acidity
• Zest of 1 lemon: Brightens the floral notes and adds fragrance
• 2 tbsp elderflower cordial: This final brushing gives the roasted rhubarb an almost candied finish

Instructions

Build your foundation:

Pulse the flour, cold butter, powdered sugar and salt in your food processor until you see pieces the size of small peas. The butter needs to stay cold for flaky results, so work quickly and dont let the processor run too long.

Bring it together:

Add the egg yolk and one tablespoon of ice cold water, pulsing just until the dough starts to clump together. Give it a squeeze, if it crumbles apart add another teaspoon of water, but err on the side of too dry rather than too wet.

Let it rest:

Shape the dough into a disc, wrap it tightly and chill for at least 30 minutes. This relaxes the gluten and firms the butter, preventing shrinkage during baking.

Shape your shell:

Roll the chilled dough on a lightly floured surface until its about 3mm thick and large enough for your 23cm tart tin. Press it gently into the tin, trim any overhang, and chill again for 15 minutes while you preheat your oven to 180°C.

Blind bake to perfection:

Line the chilled shell with parchment paper and fill with baking beans or pie weights. Bake for 15 minutes, then carefully remove the paper and beans and return to the oven for 5-7 minutes more until the bottom is golden and dry. Let it cool completely on a wire rack.

Warm your dairy:

Heat the cream and milk in a saucepan until its steaming but not boiling. You want it hot enough to temper the eggs but not so hot that they scramble on contact.

Prepare your eggs:

Whisk the yolks, sugar and vanilla until theyre pale and slightly thickened. This takes about 2 minutes with a whisk and creates a stable base for your custard.

Combine carefully:

Slowly stream about a third of the hot cream into the yolks while whisking constantly. This gradual warming prevents curdling. Pour this mixture back into the remaining cream in the saucepan.

Thicken gently:

Cook over low heat, stirring constantly with a heatproof spatula, until the custard coats the back of a spoon and leaves a clear trail when you run your finger through it. This takes 3-5 minutes, dont walk away or it will overcook.

Add the magic:

Remove from heat and immediately add the chopped white chocolate and elderflower cordial. Stir until the chocolate is completely melted and the mixture is silky smooth.

Set the filling:

Pour the custard through a fine mesh sieve into your cooled tart shell. This catches any stray bits of cooked egg. Refrigerate for at least 1 hour until its firm to the touch.

Roast the rhubarb:

Crank your oven to 190°C and arrange the rhubarb batons in a single layer in a baking dish. Sprinkle evenly with sugar, lemon zest and drizzle with elderflower cordial.

Tender roasting:

Cover tightly with foil and roast for 15 minutes, then uncover and continue roasting for 5-8 minutes more. You want the rhubarb tender but still holding its shape. Let it cool completely in the dish.

Final assembly:

Arrange the roasted rhubarb pieces over the set custard in whatever pattern pleases you. Brush the tops with a little extra elderflower cordial for shine. Return to the fridge until ready to serve.

Pin it

There was a dinner party last May where I almost didnt make this tart because I was running late, but I threw everything together anyway and it ended up being the only thing anyone talked about. Sometimes the best recipes are the ones you almost talk yourself out of making.

Getting That Crust Right

I used to struggle with tart shells that would puff up unevenly or develop soggy bottoms until I learned that proper chilling is non-negotiable. Every time you chill the dough, whether its before rolling or after shaping it into the tin, youre giving the gluten time to relax and the butter time to firm up. Blind baking might feel like an extra step, but those 20 minutes prevent a heartbreaking raw bottom layer later.

Working With Elderflower

The intensity of elderflower cordial varies wildly between brands, so I always taste my custard before pouring it into the shell. Some artisanal versions are incredibly potent while commercial brands can be more subtle. Start with the called for amount, then add more drop by drop if you want that floral note to really sing through the rich white chocolate.

Make Ahead Magic

This tart is actually better when made a day ahead, giving the flavors time to marry and the custard to fully set. I bake the crust and make the filling one day, roast the rhubarb the next morning, and assemble just before guests arrive. The rhubarb can be roasted up to two days in advance and stored in its syrup, which actually intensifies the flavor.

• If you need to transport the tart, assemble it at your destination to avoid the rhubarb sliding around
• The tart shell can be baked and frozen for up to a month, just thaw it before filling
• Leftovers keep well for 2-3 days in the fridge, though the crust will gradually soften

Pin it

Every spring I convince myself Ill try something new, but I keep coming back to this combination because sometimes classics exist for a reason. There is nothing quite like cutting into that first slice.

Frequently Asked Questions

→ What's the best way to ensure a perfectly crisp tart crust?

To achieve a crisp crust, blind bake it until golden before adding the filling. Use parchment paper and baking beans to prevent shrinking and ensure even cooking. After removing the beans, bake for a few more minutes until the base is lightly colored.

→ How can I tell if the white chocolate and elderflower custard is properly thickened?

The custard is ready when it coats the back of a spoon without running off. It should be thick enough to hold its shape somewhat but still pourable. Overcooking can lead to a grainy texture, so remove it from heat promptly as it thickens.

→ Can I prepare elements of this dessert in advance?

Absolutely! The tart shell can be baked a day ahead and stored at room temperature. The roasted rhubarb can also be prepared in advance and refrigerated. The assembled tart needs at least an hour to chill and set, making it an excellent make-ahead option for entertaining.

→ What are some creative variations or additions for this tart?

For extra texture, sprinkle toasted pistachios or almonds over the top before serving. If rhubarb isn't in season, fresh strawberries can be used as a delicious alternative. A light dusting of powdered sugar or a drizzle of extra elderflower cordial can also enhance its presentation.

→ How should I store any leftover portions?

Leftover tart should be stored in an airtight container in the refrigerator. It will generally keep well for 2-3 days. The flavors often meld and deepen slightly overnight, making it a wonderful treat the next day.