Save to Pinterest Spring arrived late that year, but the farmers market finally exploded with crimson rhubarb stalks bundled like firewood. I grabbed three bunches without thinking, then stood there wondering what to do with all of it. A friend mentioned elderflower cordial she'd brought back from a trip to the Cotswolds, and suddenly this tart made sense. The floral sweetness against tart rhubarb and white chocolate felt like capturing the entire season in one bite.
I first served this at a garden party where half the guests were late because of rain. By the time everyone arrived, the tart had been chilling for hours and the custard was flawless. Someone asked if I'd ordered it from a bakery. I didn't correct them right away.
Ingredients
- All-purpose flour: Forms the base of a buttery, crisp crust that holds up under the custard without going soggy.
- Cold unsalted butter, cubed: Keep it truly cold so the crust stays flaky and tender, not greasy.
- Powdered sugar: Dissolves faster than granulated and gives the pastry a delicate sweetness.
- Egg yolk: Binds the dough and adds richness without making it tough.
- Cold water: Just enough to bring the dough together, add it slowly to avoid a sticky mess.
- Salt: A pinch sharpens the sweetness and balances the butter.
- White chocolate, finely chopped: Use good quality with real cocoa butter, it melts smoother and tastes less waxy.
- Heavy cream: The backbone of the custard, giving it body and silkiness.
- Whole milk: Thins the custard just enough so it pours easily into the shell.
- Elderflower cordial: Adds a floral, honeyed note that makes this tart unforgettable.
- Egg yolks: Thicken the custard and give it a luxurious texture.
- Granulated sugar: Sweetens the custard and rhubarb without overpowering the delicate flavors.
- Vanilla extract: A quiet but essential backdrop that rounds out the white chocolate.
- Rhubarb, trimmed and cut into batons: Choose firm, bright stalks and cut them evenly so they roast at the same rate.
- Lemon zest: Brightens the rhubarb and keeps it from tasting one-dimensional.
Instructions
- Make the Pastry:
- 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, pulsing just until the dough clumps together, then wrap it and let it rest in the fridge for half an hour so it rolls out without shrinking.
- Blind Bake the Shell:
- Roll the chilled dough out on a floured counter, press it into your tart tin, trim the edges, and chill again briefly. Line it with parchment and baking beans, then bake until the edges are set, remove the beans, and finish baking until the base turns golden and crisp.
- Prepare the Custard:
- Heat the cream and milk until steaming, then whisk it slowly into beaten egg yolks and sugar so you don't scramble them. Return the mixture to the pan and stir gently over low heat until it thickens enough to coat a spoon, then stir in the white chocolate and elderflower cordial until smooth.
- Fill and Chill:
- Pour the warm custard into the cooled tart shell and slide it into the fridge for at least an hour. The custard will firm up beautifully and slice cleanly when you serve it.
- Roast the Rhubarb:
- Lay the rhubarb batons in a single layer, sprinkle with sugar, lemon zest, and a drizzle of elderflower cordial, then cover with foil and roast until tender but still holding their shape. Let them cool completely before arranging them on top of the custard.
- Assemble and Serve:
- Lay the roasted rhubarb over the set custard in neat rows or a casual jumble, whatever feels right. Brush with a touch more cordial if you want a glossy finish, then slice and watch everyone go quiet.
Save to Pinterest 
Save to Pinterest The first time I made this, my sister took one bite and closed her eyes. She said it tasted like walking through a garden right after the rain. I've made it a dozen times since, and it still feels like a small miracle every time the custard sets perfectly and the rhubarb glows like stained glass.
Choosing Your Rhubarb
Look for stalks that are firm and brightly colored, whether deep red or pale pink with green streaks. Thinner stalks tend to be more tender, but thicker ones hold their shape better when roasted. Always trim away any leaves, they are toxic, and peel any tough or stringy outer layers if the stalks are especially thick.
Making It Ahead
This tart is ideal for entertaining because you can bake the shell and roast the rhubarb a day in advance. The custard can be made and poured into the shell the morning of your event, then topped with rhubarb an hour before serving. It actually tastes better after a few hours in the fridge, the flavors meld and deepen.
Serving and Storing
Serve this tart cold or at cool room temperature, never warm or the custard will lose its structure. It pairs beautifully with lightly whipped cream, a handful of toasted pistachios, or just a dusting of powdered sugar. Leftovers keep covered in the fridge for up to three days, though the crust will soften slightly over time.
- Use a sharp knife dipped in hot water and wiped clean between slices for neat edges.
- If the custard seems too soft after chilling, give it another 30 minutes in the coldest part of your fridge.
- Swap strawberries or poached apricots for rhubarb if the season shifts or you want a different flavor.
Save to Pinterest 
Save to Pinterest This tart has become my answer to spring celebrations, from Easter lunches to birthday dinners where someone asks for something special. It never fails to feel both impressive and comforting, like a hug dressed up in pastry and flowers.
Recipe Questions & Answers
- → Can I make this tart ahead of time?
Yes, this is an excellent make-ahead dessert. You can prepare the tart shell and custard filling up to 2 days in advance. The rhubarb can be roasted a day ahead and stored in the refrigerator. Assemble the tart a few hours before serving for the best presentation.
- → What can I use instead of elderflower cordial?
If elderflower cordial is unavailable, try orange blossom water, rose water, or a splash of lemon juice with a touch of honey. You can also use vanilla extract for a more classic flavor profile, though you'll lose the distinctive floral notes.
- → How do I prevent the tart crust from becoming soggy?
Blind baking the crust fully until golden is essential. Make sure the crust is completely cooled before adding the custard filling. You can also brush the baked shell with a thin layer of melted white chocolate before adding the custard for extra protection.
- → Can I use frozen rhubarb instead of fresh?
Fresh rhubarb is recommended for the best texture and presentation. Frozen rhubarb tends to release more liquid and may become too soft when roasted. If using frozen, thaw and drain thoroughly, then reduce the roasting time slightly.
- → How should I store leftovers?
Store the tart covered in the refrigerator for up to 3 days. The crust may soften slightly over time, but the flavors will remain delicious. Bring to cool room temperature before serving for the best taste and texture.
- → What type of white chocolate works best?
Use good-quality white chocolate with at least 20% cocoa butter for a smooth, creamy custard. Avoid white baking chips or compound coatings, as they don't melt as smoothly and may result in a grainy texture.