Rhubarb Panna Cotta Tart
For years, my favorite British cookbook authors have taunted me with their blithe references to winter tarts and cakes and pavlovas made with “forced rhubarb.” (Example: Nigella Lawson, How To Be a Domestic Goddess, page 107, “Rhubarb Tart”: “This is perfect for January, when the new season’s forced rhubarb is just in, rosy and budding with its rhubarbiness.”)
For the last few years, I’ve spent winters searching the groceries and markets of New York City, and then Washington, D.C., for this elusive “forced rhubarb” with no luck. Last year, my beloved rhubarb finally appeared in D.C. in late April (APRIL!).
Then, this January, I was at a Whole Foods in New York City picking up groceries for some friends I was staying with, and there it was–rhubarb! In January! I lingered in the produce section for a few minutes, debating whether to buy the whole lot and bring it back with me on the train to D.C. Ultimately, I resisted the temptation, reasoning, if a Whole Foods in New York now had forced rhubarb, surely one in D.C. would, too?
When I returned home to Washington, I visited my regular Whole Foods with high hopes. No luck. I went to two other Whole Foods in town. Again no luck. I resigned myself, again, to a rhubarb-less winter.
Then, a couple of weeks ago, I was at my local, non-fancy Harris Teeter, buying grapefruits and kiwis for a winter-appropriate tart, and I saw it: Gorgeous, fuschia, definitely rhubarb. I immediately grabbed a pound.
Admission: I originally wanted to attempt a rhubarb panna cotta tart because I envisioned it as a clean pink canvas to display dozens of rhubarb roses. However, when I actually got around to shaping the roses, they were even more fiddly than usual. (The problem was probably that the forced rhubarb stalks, though fantastically and gorgeously pink, were quite thin.) I decided to go with rhubarb ribbons instead, and I actually ended up loving the ribbon-decked tart even more than the rose-strewn version I had envisioned. I mean:
The rhubarb flavor here is distinct but subtle. Next time, I may experiment with increasing the quantity of rhubarb for more intense color and flavor. Or I may not. This perfectly pink, not-too-sweet tart is pretty lovely as it is.
Rhubarb Panna Cotta Tart
The rhubarb panna cotta filling for this tart was cobbled together from a number of internet sources, but mostly this blackberry panna cotta recipe. The tart shell is my go-to sweet shortcrust pastry from the cookbook Soulful Baker, by Julie Jones. The rhubarb flavor here is definite but subtle. For a more intensely rhubarb filling, feel free to experiment with increasing the amount of rhubarb. (See Notes.)
- 230 g all-purpose flour
- 125 g unsalted butter, chilled and diced
- 50 g powdered sugar
- 1 egg yolk
- 2 tbsp whole milk
To glaze the tart shell:
- 1 egg yolk
- a couple of drops of boiling water
Rhubarb Panna Cotta Filling
- 2 cups (approx. 1/3 lb.) chopped rhubarb — the pinkest you can find!
- 2 tsp water
- 1/3 cup / 67 g granulated sugar
- 2 cups heavy cream
- 1/2 tsp vanilla bean paste
- 1 3/4 tsp powdered gelatin
- 3 1/2 tbsp cold water
- rhubarb ribbons or rhubarb roses See Notes.
Make the tart shell:
Place the flour and butter in the bowl of a stand mixer fitted with a paddle attachment. Beat on low speed until the mixture resembles fine breadcrumbs.
Add the powdered sugar to the bowl, and beat gently until just combined.
Add the egg yolk and milk, turn the speed up to medium-low (2 or 3 on a KitchenAid stand mixer), and mix until the dough just starts to come together.
Gather the dough mixture in a piece of plastic wrap, bringing it together into a ball, and then flattening the ball into a disk about 1/2 inch thick.
Chill the pastry dough in the refrigerator for at least one hour.
When the dough is chilled, roll it out between two pieces of parchment paper (this will allow you to avoid adding more flour) until it is about 1/8 inch thick.
Remove the top sheet of parchment and transfer the dough (parchment side up) to a 9-inch fluted tart pan. Remove the remaining parchment and gently press the dough into the pan. Trim the edges so that the pastry extends about 1/2 inch beyond the top of the pan. (You want a bit of overhang.) Use the handle of a wooden spoon to gently press the the pastry into the fluted sides of the pan. Reserve the extra dough.
Place the tart shell in the refrigerator and chill for about 30 minutes.
Meanwhile, preheat the oven to 400 F.
Remove the tart shell from the refrigerator, place it on a baking sheet, and prick the bottom all over with a fork at 1 inch intervals. Line the pastry with a crumpled up piece of parchment paper, and fill the shell with pie weights, dried beans, or rice.
Blind bake the tart shell for 15 minutes. Then take the baking sheet with tart shell out of the oven, carefully remove the parchment and pie weights, and return to the oven to bake for an additional five minutes, until the dough loses its “raw” look.
Remove the pan from the oven again. If there are any cracks or holes, patch them with the reserved dough. Mix the remaining egg yolk with a couple of drops of boiling water, and brush the inside of the tart shell with the egg yolk mixture.
Return the tart shell to the oven and bake for another 15 minutes.
Remove the tart shell from the oven to a wire rack and allow it to cool, still on the baking sheet.
When the tart shell is cool, use a Swiss vegetable peeler to carefully shave away the overhang. Using a clean, soft, pastry brush or paintbrush, gently sweep out any crumbs that have fallen into the bottom of the shell.
Make the panna cotta filling:
In a small saucepan, combine the rhubarb, 2 teaspoons of water, and sugar. Cover and simmer over low heat until the rhubarb completely breaks down. Cool until just warm. Taste the mixture–if it is too tart, add a bit more sugar.
Add the cream to the rhubarb, and re-heat the rhubarb-cream mixture over low heat until just steaming (160-170 F). Remove from the heat, and allow the mixture to steep for 30 minutes.
Toward the end of the 30 minutes, place the 3.5 tablespoons of cold water in large, spouted container. (I used a 4-cup capacity Pyrex measuring cup.) Sprinkle the powdered gelatin over the cold water.
Return the rhubarb-cream mixture to the stove, and re-heat again until just steaming (160-170 F). Stir in the vanilla bean paste.
Place a fine mesh sieve over the container with the now softened gelatin, and pour in the rhubarb-cream mixture through the sieve, using a rubber or silicone spatula to stir and press rhubarb-y cream to extract every last bit of lovely pink liquid. When you’ve extracted as much liquid as possible, thoroughly whisk the rhubarb-cream mixture into the softened gelatin.
Place the tart shell, still on the baking sheet, in the refrigerator on a low shelf.
Carefully pour the filling into the tart shell, then leave the tart in the refrigerator to set overnight, or for at least four hours.
The rhubarb flavor here is definite but subtle. For more intense rhubarbiness-both flavor- and color-wise, feel free to try increasing the amount of rhubarb in the filling. (You’ll probably also want to increase the sugar proportionally.)
I kept the amount of vanilla bean paste in the panna cotta small because I wanted rhubarb to dominate. Feel free to try increasing it to 1 teaspoon for more of a “Vanilla-Rhubarb Panna Cotta.”
If you don’t have vanilla bean paste, vanilla extract would probably work, too. Or you could scrape in the seeds of half a vanilla bean.
The rhubarb ribbons (or rhubarb roses) are obviously optional–but so pretty! I created my ribbons following the basic technique outlined in this recipe on the Martha Stewart website. If you want to try your hand at rhubarb roses, see the instructions in my blog archives.