Save The smell of roasted rhubarb still brings me back to a rainy Sunday in late April when I decided to experiment with something more ambitious than my usual fruit crumbles. I had a bottle of elderflower cordial sitting in the cupboard and a bunch of rhubarb from the farmers market that was begging to be used. White chocolate seemed like a risky pairing at first, but the moment that creamy custard met the sharp tang of the rhubarb, I knew I had stumbled onto something special. It looked almost too pretty to eat, which of course didn't stop anyone.
I first made this tart for a friend's baby shower, and I remember feeling nervous about whether the flavors would work for a crowd. One guest, who claimed she hated rhubarb, came back for a second slice and asked for the recipe on the spot. That's when I realized this dessert had the power to change minds. The elderflower adds a delicate floral note that feels fancy without being fussy, and the rhubarb stays just firm enough to hold its shape on top of that silky custard.
Ingredients
- All-purpose flour: Forms the base of your tart crust and should be measured carefully, I learned the hard way that too much makes it tough and crumbly.
- Cold unsalted butter: The key to a flaky crust is keeping this cold, I even pop my cubed butter in the freezer for 10 minutes before starting.
- Powdered sugar: Sweetens the crust gently and helps create that melt in your mouth texture that makes shortcrust pastry so irresistible.
- Egg yolk: Binds the dough together and adds richness, and don't toss that leftover white, save it for meringues or an omelet.
- Cold water: Just enough to bring the dough together without making it sticky, add it gradually and stop as soon as it starts to clump.
- White chocolate: Choose good quality white chocolate with cocoa butter listed as the first ingredient, the cheap stuff just won't melt as smoothly.
- Heavy cream: Creates the luscious custard base and should be full fat for the best texture and flavor.
- Whole milk: Lightens the custard just a touch so it's creamy but not overly heavy after a full meal.
- Elderflower cordial: Brings a subtle floral sweetness that pairs beautifully with both the white chocolate and the rhubarb, if you can't find it, a splash of rose water works too.
- Egg yolks: Thickens the custard and gives it that gorgeous pale yellow color, whisk them well with the sugar until they're smooth and pale.
- Granulated sugar: Sweetens both the custard and the roasted rhubarb, balancing out the tartness perfectly.
- Vanilla extract: A little goes a long way and it deepens the flavor of the custard in a way that feels warm and comforting.
- Rhubarb: The star of the show, look for firm stalks with bright color and avoid any that feel limp or have brown spots.
- Lemon zest: Brightens the rhubarb and adds a citrusy pop that keeps everything from feeling too sweet or one note.
Instructions
- Make the Tart Crust:
- Pulse the flour, cold butter, powdered sugar, and salt in a food processor until it looks like coarse breadcrumbs, then add the egg yolk and cold water a little at a time until the dough just starts to clump. Shape it into a flat disk, wrap it tightly in plastic, and let it chill in the fridge for at least 30 minutes so it's easy to roll out without shrinking.
- Roll and Blind Bake:
- Roll the chilled dough on a floured surface until it's large enough to fit your tart tin, press it gently into the corners, trim the edges, and chill again for 15 minutes to prevent shrinking. Line with parchment, fill with baking beans, and bake at 180 degrees C for 15 minutes, then remove the beans and parchment and bake another 5 to 7 minutes until golden and crisp.
- Prepare the Custard:
- Heat the cream and milk in a saucepan until steaming, then whisk the egg yolks, sugar, and vanilla in a bowl until pale and thick. Slowly pour the hot cream into the yolks while whisking constantly to temper them, return everything to the pan, and stir over low heat until the mixture thickens just enough to coat the back of a spoon.
- Finish the Custard:
- Remove the custard from the heat and stir in the chopped white chocolate and elderflower cordial until everything is smooth and glossy. Pour it into the cooled tart shell and chill in the fridge for at least an hour until the custard is completely set and firm to the touch.
- Roast the Rhubarb:
- Arrange the rhubarb batons in a single layer in a baking dish, sprinkle with sugar and lemon zest, drizzle with elderflower cordial, and cover with foil. Roast at 190 degrees C for 15 minutes, then uncover and roast another 5 to 8 minutes until the rhubarb is tender but still holds its shape, then let it cool completely before topping the tart.
- Assemble and Serve:
- Arrange the cooled rhubarb pieces over the set custard in whatever pattern makes you happy, brush with a little extra elderflower cordial if you want extra shine, and keep it chilled until you're ready to slice and serve.
Save There's something about slicing into this tart that feels like a small celebration, even on an ordinary weeknight. The way the custard stays perfectly smooth and the rhubarb glistens on top makes everyone pause for just a moment before diving in. I've served this at birthdays, dinner parties, and once just because it was a particularly nice Tuesday, and every time it feels a little bit magic.
How to Store and Make Ahead
This tart actually gets better after a night in the fridge, which makes it perfect for entertaining when you don't want to be stuck in the kitchen while guests arrive. You can bake the crust up to two days ahead and keep it wrapped tightly at room temperature, then make the custard and roast the rhubarb the day before serving. Just assemble the whole tart a few hours before you plan to serve it, and keep it chilled until the last minute. Leftovers will keep covered in the fridge for up to three days, though in my experience they rarely last that long.
Flavor Variations and Swaps
If rhubarb isn't your thing or it's out of season, roasted strawberries or a mix of berries work beautifully with the white chocolate and elderflower. You can swap the elderflower cordial for a splash of rose water or orange blossom water for a different floral note, or leave it out entirely and add a little extra vanilla. I've also tried this with dark chocolate instead of white, and while it's delicious, it loses that delicate springtime feeling that makes this tart so special.
Serving Suggestions
This tart is rich enough to stand on its own, but a small dollop of lightly sweetened whipped cream or creme fraiche on the side cuts through the sweetness nicely. I love serving it with a glass of chilled Moscato or even a sparkling elderflower cordial spritz for guests who don't drink wine. For a little crunch and color, sprinkle toasted pistachios or slivered almonds over the top just before serving.
- Serve chilled or at cool room temperature for the best texture and flavor.
- A light dusting of powdered sugar just before serving makes it look even more elegant.
- Pair with fresh mint tea or a floral white wine to highlight the elderflower notes.
Save This tart has become my go to when I want to impress without the stress, and every time I make it I'm reminded why simple ingredients treated with care always win. I hope it brings as much joy to your table as it has to mine.
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 24 hours in advance. Roast the rhubarb and assemble just a few hours before serving for the best presentation and texture.
- → What can I substitute for elderflower cordial?
If elderflower cordial is unavailable, try using a light floral honey diluted with a splash of lemon juice, or a vanilla simple syrup. The flavor profile will change slightly, but the tart will still be delicious.
- → How do I prevent the tart crust from becoming soggy?
Blind baking the crust thoroughly until golden is essential. Additionally, ensure the custard has cooled slightly before pouring into the shell, and only add the roasted rhubarb when it has completely cooled to avoid excess moisture.
- → Can I use frozen rhubarb instead of fresh?
Fresh rhubarb works best for this tart as it holds its shape better when roasted. If using frozen, thaw completely and pat very dry with paper towels before roasting, and reduce the roasting time slightly to prevent it from becoming too soft.
- → What type of white chocolate should I use?
Choose a good quality white chocolate with at least 28% cocoa butter for the smoothest, creamiest custard. Avoid white baking chips or candy coating, as they won't melt properly and may result in a grainy texture.
- → How long will this tart keep in the refrigerator?
The assembled tart is best enjoyed within 24 hours for optimal texture and flavor. The rhubarb may release some juice over time, though the tart will still taste delicious for up to 2 days when properly refrigerated.