Don’t panic. This looks like a crazy long and complicated recipe, but it’s not so bad. It does require a little prep the day before to macerate the rhubarb and make the dough, but then it’s smooth sailing for the rest of the recipe. And having an elegant, modern rhubarb dessert in your arsenal is worth it! Not only is it beautiful to look at, but the buttery crumbs, tart layer of rhubarb and nutty brown butter filling make it especially memorable.
Of course, I did modify a few things. For one, I added salt. I know, the gall to change a Thomas Keller recipe. But here’s the thing: I like a touch of salt in my desserts. I feel it brings out the flavors, gives the dessert more dimension and, honestly, prevents it from tasting fake and manufactured. Secretly, I think the flawless, meticulous taste of desserts from some pastry shops is from not enough (or any) salt. And the result is desserts that are boring, flat and not that remarkable. It’s just a theory and I've never had Thomas Keller's desserts in person, so I have no idea how they actually taste. I highly doubt they're flat and boring. But this specific recipe had no salt in it, and when I bake, be it sweet or savory, I always include salt. The good news is you can decide for yourself which side of the salted dessert debate you want to be on. Ultimately, the difference is very small and I'm just being knit picky.
The other very minor change I made was the egg measurement. Literally no one has the time, or desire, to whip up a bunch of eggs and measure them out by the tablespoon. I know precision is the key to baking, but sometimes you just have to live dangerously, and I made a few calculations based on average egg volume so we can all make this tart with a whole number of eggs. As far as I could tell, the tart was fine.
Finally, as far as scheduling goes, this is my recommendation:
macerate the rhubarb
make the pâte sucrée dough
make the almond streusel
roll out the dough and bake the tart shell
make the brown butter filling
bake the almond streusel while the tart shell cools
assemble the tart, bake, cool, top with streusel and enjoy!
Easy day! I hope this tart livens up your Spring baking!
brown butter rhubarb tart with toasted almond streusel
makes 12 large bars | recipe from Thomas Keller's Bouchon Bakery
15 young rhubarb stalks, about 2 lbs (900 g), preferably at least 13" long and about 1/2" wide
1/2 cup (100 g) granulated sugar
1/4 cup + 2 tbsp (120 g) grenadine - helps color the rhubarb
2 2/3 cups (375 g) all-purpose flour
1/4 cup + 2.5 tbsp (46 g) powdered sugar
3/4 cup + 1 tbsp (94 g) powdered sugar
1/4 cup + 3 tbsp (47 g) almond flour/ meal
2 sticks (8 oz, 225 g) unsalted butter, room temperature
1/2 vanilla bean, split lengthwise (I used 1 tsp vanilla extract)
1 tsp kosher salt
1 large egg (*recipe advised 3.5 tbsp or 56 g), lightly beaten
TOASTED ALMOND STREUSEL
4 tbsp all purpose flour
5 tbsp almond meal
3 tbsp granulated sugar
1/4 tsp kosher salt
3 tbsp unsalted butter, cold, cut into 1/4" pieces
BROWN BUTTER FILLING
1/2 cup + 3 tbsp (75 g) almond flour/ meal
1/2 cup + 1.5 tsp (75 g) all-purpose flour
3 large eggs (*recipe advises 1/2 cup + 1.5 tbsp or 150 g), lightly beaten
1 cup + 1 tbsp (210 g) granulated sugar
1/2 tsp kosher salt
1/4 cup + 2 tsp (75 g) whole milk
1/4 cup + 1 tbsp (75 g) heavy cream
3/4 cup + 1 tbsp (13 tbsp or 165 g) brown butter, warm
Trim the rhubarb so it fits lengthwise in a 9"x13" baking dish. Using a paring knife (a vegetable peeler would remove too much), beginning at one end of each stalk, pull off the strings and any tough peel running the length of the rhubarb; if any stalks are very young and green and don't trim easily, they can be left unpeeled. **Note: Don't forget this part and decide to do it after the rhubarb has been soaking in the sugar for 4 hours. It's a sticky mess.
Arrange the rhubarb in the baking dish. Sprinkle with the sugar and drizzle the grenadine over the top. Cover with plastic wrap and refrigerate for 24 hours, turning and tossing the rhubarb every 8 hours to coat it evenly. (The sugar will pull out the moisture in the rhubarb as it sits.)
Drain the rhubarb on paper towels; discard the liquid in the pan.
Place the all-purpose flour in a medium bowl. Sift the 1/4 cup + 2.5 tbsp powdered sugar and almond flour into the bowl; break up any lumps of almond flour remaining in the sieve, add them to the bowl, and whisk to combine.
Place the butter in the bowl of a stand mixer fitted with the paddle attachment and cream on medium-low speed, warming the bowl as needed, until the butter is the consistency of mayonnaise and holds a peak when the paddle is lifted. Sift in the remaining 3/4 cup + 1 tbsp powdered sugar and the salt and pulse to begin incorporating the sugar, then increase the speed to medium-low and mix for about 1 minute, until the mixture is fluffy. Scrape down the sides and bottom of the bow. Scrape the seeds from the vanilla bean (or add the extract), add them to the butter mixture, and mix on low speed for about 30 seconds to distribute the seeds evenly.
Add the dry ingredients in 2 additions, mixing for 15 to 30 seconds after each, or until just combined. Scrape the bottom of the bowl to incorporate any dry ingredients that have settled there. Add the egg and mix on low speed until just combined, 15 to 30 seconds.
Transfer the dough to the work surface. Use the heel of your hand to smear the dough and work it together. Divide the dough in half and form each half into a 4"x6" rectangle, about 3/4" thick (but I left it in one piece and had no issues).
Wrap each piece in plastic wrap. Refrigerate until firm, about 2 hours, but preferably overnight. The dough can be refrigerated for up to 2 days or frozen for up to a month.
Preheat the oven to 350 F. Spray the quarter sheet pan with nonstick spray. Line the bottom with parchment paper.
Roll out the dough to a 12" x 16" rectangle, just under 1/8" thick. Line the sheet pan, and then line the shell with parchment paper. Fill the shell will raw rice (I used beans, but Keller advises against beans because they will leave an imprint in the dough, unlike rice).
Bake for 15 minutes, then rotate the pan and bake for another 15- 20 minutes, until the dough is set and no longer sticks to the parchment paper.
Remove the parchment and rice (or beans, and store for future use), return the pan to the oven, and bake another 15 minutes, or until the dough is golden brown. Set the pan on a cooling rack and cool completely.
TOASTED ALMOND STREUSEL
Combine the all-purpose flour, almond flour, sugar, and salt in a bowl and whisk to break up any lumps.
Add the butter and toss to coat the pieces. Work the mixture with your fingertips, breaking the butter into pieces no larger than 1/8" and combining it with the flour mixture. Do not overwork the mixture or allow the butter to become soft; if it does, place the bowl in the refrigerator to harden the butter before continuing.
Transfer the streusel to a covered container or resealable plastic bag. Refrigerate for at least 2 hours, or up to 2 days, or freeze for up to 1 month.
Preheat the oven to 325 F.
Spread the cold streusel in an even layer on a sheet pan. Bake for about 12 minutes, turning the streusel with a metal spatula every 4 minutes, until it is golden brown and dry. Place the pan on a cooling rack and let cool completely. **Note: watch very carefully if your oven is finicky. The streusel can brown/ burn very quickly.
Pour the streusel into a food processor and pulse to the consistency of brown sugar (I skipped this part in favor of a crunchier texture and to avoid dirtying the food processor). The streusel can be stored in a covered container for up to 2 days.
BROWN BUTTER FILLING
Whisk together the almond flour and all-purpose flour in a medium bowl, breaking up any lumps in the almond flour.
Combine the eggs, sugar, and salt in the bowl of a stand mixer fitted with the whisk attachment and mix on medium speed for about 2 minutes, until thickened. With the mixer running on medium-low, slowly add the milk and cream. Add the dry ingredients and mix on medium- low for a few seconds, until combined. With the mixer running, slowly add the brown butter and mix to combine. Transfer the filling to the pastry bag (I found a spoon worked fine).
Pipe (or spoon) enough of the filling into the crust to cover the bottom with 1/4" thick layer, and spread it evenly with a small offset spatula. Arrange the rhubarb rounded side up on top of the filling, running lengthwise in the pan (if any pieces are shorter than the pan, patch them with a piece cut from another stalk). Pipe (or spoon) the filling around the stalks, filling in any gaps, then spread any remaining filling over the top of the rhubarb (it may not be completely covered).
Bake for 40 minutes. Rotate the pan, reduce the oven temperature to 325 F, and bake for another 10 to 15 minutes, until the filling is set and golden. Set the pan on a cooling rack and cool completely.
To serve: lift the tart out of the pan with a large spatula and trim the edges of the crust (alternatively: cut into 12 pieces and remove pieces from pan individually). Cut into 12 pieces and garnish each piece with some streusel topping. Dust the tops lightly with powdered sugar.