Pistachio Lemon Cake From 'Dolci' by Renato Poliafito

Directions

1. Make the cake: Preheat the oven to 350°F (180°C) and set a rack in the center. Coat two 8-inch (20 cm) round cake pans with cooking spray, line with parchment rounds, and dust with flour, knocking out any excess.
2. In a stand mixer fitted with the paddle, mix the flour, sugar, baking powder, and salt on low speed. Add the butter, one piece at a time and mix until it resembles coarse sand. In a small bowl, whisk the milk and egg yolks. Add half the milk mixture to the mixer and mix on medium speed for 30 seconds. Stop to scrape down the sides, then add the remaining milk mixture and mix on medium speed until smooth and fluffy, about 1 minute. Add the vanilla extract, almond extract, and pistachio spread and mix until just combined. Transfer the batter to a large bowl.
3. Wash and dry the stand mixer bowl, then return to the stand mixer and snap on the whisk. Beat the egg whites on high speed until medium peaks form, about 3 minutes. Add half of the whites to the bowl with the batter and fold in. Add the chopped pistachios and remaining egg whites and fold until just a few streaks remain. Divide the batter between the prepared pans.
4. Bake until a cake tester comes out clean, 40 to 50 minutes, rotating the pans halfway through. Cool in the pans for 30 minutes, then turn out onto a wire rack to cool completely.
5. Make the filling: In a stand mixer with the paddle, mix the butter until smooth. Sift the powdered sugar and add to the mixer, followed by the salt, scraping down the bowl as needed.
6. Add in the mascarpone and mix until incorporated. Add in the pistachio spread and mix until the filling begins to thicken and emulsify, at least 30 to 45 seconds. Use immediately or refrigerate until ready to use. (If cold, let the filling soften at room temperature before spreading.)
7. Just before assembling, make the frosting: In a stand mixer fitted with the whisk, beat the the egg whites on medium speed until soft peaks form, about 3 minutes. In a small saucepan, combine the sugar and 85 grams (6 tablespoons) water and stir once to combine. Set over low heat and bring the mixture to a boil until the syrup has reached 238° to 240°F (114° to 116°C) on a candy thermometer. With the mixer on low speed, slowly stream the syrup into the egg whites. Once all the syrup is incorporated, increase the speed to high and whip until the steam dissipates and soft, glossy peaks form, 6 to 8 minutes. Add the butter one piece at a time and beat until the buttercream looks thick, fluffy, and spreadable, about 10 minutes. Add the white chocolate and beat until incorporated (if making in advance you store in the fridge prior to adding the lemon zest. The buttercream can be stored in an airtight container in the refrigerator for 7 to 10 days. Let sit at room temperature for 15 minutes and whisk to fluff before using.) Add the lemon zest and lemon juice and beat until smooth and incorporated, about 3 minutes.
8. To assemble the cake, use a serrated knife to trim off the tops of both cake layers, creating an even surface. Place one cake layer, cut-side up, on a turntable cake stand or serving plate. Fit a piping bag with a large round tip. Put about 85 grams (1/2 cup) of buttercream in the bag and pipe a border around the edge of the cake to help contain the filling. Spoon all of the filling in the center of the cake layer. Use a small offset spatula to spread in an even layer out to the buttercream border.
9. Place the second cake layer, cut-side down, on top of the filling and frosting. Top the cake with 170 grams (1 cup) of the buttercream, spreading a thin layer on the top and sides of the cake as a “crumb coat.” Place the cake in the refrigerator for 15 to 20 minutes to set.
10. Use the remaining frosting to frost the sides and top of the cake. Any remaining pistachios, buttercream, and filling can be used to accent the top of the cake (as seen in the photo).
11. This cake can be covered and refrigerated for up to 3 days.