rhubarb buttermilk

Ingredients

• 212 grams | 2 ¾ cups almond flour
• 212 grams | 1 ¾ cups confectioners’ sugar
• 172 grams | ⅔ cup egg whites
• 235 grams | 1 cup plus 3 tablespoons granulated sugar
• 150 grams | ⅔ cup water
• 40 grams | ¼ cup fresh red currants

• 75 grams | ⅓ cup egg yolks
• 2.3 grams | 1 sheet gold gelatin, bloomed in ice water and
• wrung gently of excess water
• 40 grams | ¼ cup sugar
• 150 grams | 5 ounces white chocolate, chopped
• 165 grams | ½ cup plus 2 ½ tablespoons heavy cream
• 60 grams | ¼ cup buttermilk
• 50 grams | ¼ cup cultured yogurt
• macaroon crust

1. FOR THE MACAROON CRUST: Preheat the oven to 325°F (165°C). Line 2 quarter sheet pans with parchment paper and spray the paper with nonstick cooking spray. Combine the almond flour and confectioners’ sugar in a food processor and mix for about 2 minutes, until a fine powder forms. Pass the mixture through a tamis into a large bowl. Add the egg whites to the flour mixture and mix with a rubber spatula to create a smooth batter. Combine the granulated sugar and water in a small, heavy saucepan and heat to 248°F (120°C) while stirring occasionally. Let the syrup cool to about 180°F (82°C) and add the currants. When the syrup has turned a deep red, after about 10 minutes, strain it through a chinois into a bowl and discard the currants. Fold the syrup into the batter with a rubber spatula, mixing well. Divide the batter evenly between the 2 prepared quarter sheet pans and bake for 8 minutes, until the surface is dry but not brown. Let cool in the pans at room temperature for 1 hour. Using a bread knife, even off the top and sides of each macaroon sheet, keeping the sheets the same dimensions. Line a quarter sheet pan with plastic wrap and place a macaroon sheet in the pan. Reserve the second sheet.
2. FOR THE BUTTERMILK PARFAIT: Put the egg yolks in the bowl of a stand mixer fitted with the whip attachment and mix on high speed for about 8 minutes, until the yolks have doubled in volume. Meanwhile, combine the gelatin and sugar in a small saucepan and heat to 248°F (120°C). When the egg yolks are ready, pour in the gelatin mixture and continue to whip until the yolks fall in a ribbon when the whip is lifted.
3. When the egg yolks are nearly ready, heat the chocolate in a double boiler over gently simmering water just until melted, stirring occasionally. Remove from over the heat and fold in the egg yolks, mixing thoroughly. Then fold in 35 grams (2 ½ tablespoons) of the cream and all of the buttermilk until uniformly combined. Reserve in the refrigerator.
4. Combine the remaining 130 grams (½ cup) of cream and the yogurt in the stand mixer fitted with the whip attachment and whip on high speed until stiff peaks form. Fold the cream mixture into the chocolate mixture just until combined, then pour evenly over the macaroon sheet in the sheet pan. Place the reserved macaroon sheet, top side down, on top of the parfait. Line a second quarter sheet pan with plastic wrap, place on top of the stacked macaroon sheets, and press lightly. Freeze in this formation for at least 3 hours, until completely frozen. Using a sharp knife, cut into 1 by 3-inch (2.5 by 7.5-centimeter) pieces. Store in an airtight container in the freezer.
5. FOR THE BUTTERMILK ESPUMA: Prepare an ice bath. Combine the buttermilk, cream, and 20 grams (5 teaspoons) of the sugar in a saucepan and heat to 130°F (54°C). Meanwhile, combine the remaining 5 grams (1 ¼ teaspoons) of sugar and the cream stabilizer in a bowl and mix well. Slowly add the warm buttermilk mixture to the sugar mixture while using an immersion blender to dissolve the sugar mixture. Nest the bowl in the ice bath to cool the mixture. Transfer to a siphon canister and charge with 2 nitrous oxide cartridges. Refrigerate for 1 hour before use.
6. FOR THE RHUBARB PUREE: Preheat the oven to 325°F (165°C). Put the rhubarb in a metal pan. Combine the simple syrup and verjus in a small saucepan and bring to a boil over high heat. Remove from the heat, pour over the rhubarb, and cover the pan with aluminum foil. Bake for 10 minutes, until very tender. Meanwhile, prepare an ice bath. When the rhubarb is ready, drain it, discarding the liquid, and transfer to a blender. Mix on high speed for about 3 minutes, until a smooth puree forms. Strain through a chinois into a bowl, then nest the bowl in the ice bath to cool the puree. Season with sugar, transfer to a squeeze bottle, and reserve in the refrigerator.
7. FOR THE COMPRESSED RHUBARB: Combine the rhubarb, water, and sugar in a shallow plastic container. Put the entire container into the chamber of a vacuum seal machine. Compress twice with full vacuum and store in the refrigerator for at least 1 hour before use.
8. FOR THE CARAMELIZED WHITE CHOCOLATE SALAD: Preheat the oven to 250°F (120°C). Put the white chocolate in a metal pan, cover with aluminum foil, and bake for 20 minutes, until the chocolate is golden brown. Remove from the oven and let cool to room temperature. Refrigerate the chocolate to crystallize it. Break into small pieces about the size of a pistachio. (If not using right away, store in an airtight container in a cool, dry area.) Combine the white chocolate pieces, pistachios, and sorrel stems in a small bowl. Add the compressed rhubarb pieces and dress with a small amount of the rhubarb liquid.