Pistachio Celebration Cake With Whipped Custard Cream

Directions

1. For the pistachio sheet cake:
2. Heat the oven to 350°F. Grease a 13x18-inch sheet pan or 9x13 baking dish with nonstick spray or butter. If using a sheet pan, measure and cut a 13x26-inch sheet of parchment paper and place into the pan so that 4 inches of overhang remain on the sides of the pan. If using a 9x13-inch dish, cut a 9x21-inch sheet of parchment paper and follow the same placement, leaving an overhang on the sides of the dish.
3. Add the softened butter, oil, and sugar to the bowl of a stand mixer fitted with a whisk attachment. Whip fats and sugars on medium-high speed for 3 to 4 minutes, until the mixture is pale and sugar has mostly absorbed.
4. Add the one full egg and vanilla extract to the stand mixer bowl and combine on low speed for about 15 seconds. Add the egg whites to the rest of the ingredients, then whip the mixture on medium for another 4 to 5 minutes, until everything is fluffy and white.
5. Place the pistachios in a blender or food processor and pulse for 1 to 2 minutes, until they are mostly crumby and sandy. Set aside ¼ cup of the ground pistachios for decorating later. Place the rest of the ground pistachios in a large mixing bowl. Add the flour, baking powder, baking soda, and salt to the pistachios and whisk everything together until the mixture is cohesive.
6. Using a rubber spatula, add ⅓ of the wet ingredients to the large mixing bowl and fold together until just combined, making sure to scrape the bottom of the bowl. Add ½ cup of buttermilk and repeat the folding and scraping. Add another ⅓ of the wet ingredients, then fold and scrape the bowl. Repeat with the remaining buttermilk and wet ingredients. Once no streaks of liquid or dry remain, transfer the batter into your greased and lined pan, using the back of a spatula to spread it into an even layer.
7. Bake for 30 to 35 minutes, or until the center top of the cake is deep golden brown and bouncy to the touch. If the cake is browning but not yet set in the middle, place a large sheet of aluminum foil lightly on top of the cake while it finishes baking.

1. For the whipped custard cream and assembly:
2. Add the sugar, cornstarch, and salt to a medium-sized saucepan and whisk together until the sugar granules have broken up any clumps of cornstarch. Set aside.
3. To a medium-sized bowl, add the 4 reserved egg yolks and whole milk, then whisk until no streaks of yellow remain. Set aside.
4. In a small bowl, measure out the butter and vanilla. Set aside.
5. Place the saucepan over medium heat and slowly pour in the egg and milk mixture. Whisk constantly while the custard comes to a simmer and it begins to foam. Keep whisking, scraping the bottom of the pan, while the custard begins to bubble. Cook for a total of 5 to 7 minutes.
6. Remove the pan from the heat when the custard has thickened to a brownie batter consistency and the whisk leaves visible traces in the custard. Add the butter and vanilla extract and continue to whisk as it finally thickens to a pudding-like thickness. If the custard is not holding onto the whisk, heat it over a low flame for another 1 to 2 minutes until properly thickened.
7. Immediately transfer the custard into an 8x8-inch baking dish or large, wide bowl. Cut a large sheet of saran wrap and press it onto the surface of the custard, making sure every inch of exposed custard is making contact with the saran wrap. This prevents the custard from forming a “skin” while it cools in the fridge for 2 hours, or until cold to touch. The custard can be made and stored in the fridge up to 3 days in advance.
8. Once the cake and custard have cooled and are ready to assemble and serve, remove the cake from the pan using the overhang of parchment paper to lift the cake out and onto a large board. (Alternatively, the cake could be served right in its baking vessel, as well.)
9. In a stand mixer or large bowl, whip the heavy cream for 3 to 5 minutes until stiff peaks form. Remove the custard from the fridge and use a spatula to stir it and loosen it up. Add ¼ of the whipped cream to the custard and use the spatula to fold it into the custard to further lighten the mixture. Once incorporated, add the lightened custard into the bowl with the whipped cream and gently fold together.
10. In a small bowl, stir the jam, lemon juice, and salt together until the jam is runnier and less sweet to taste.
11. Assemble the cake by slathering on the custard cream and dolloping spoons of the jam mix. Swirl with a knife or spoon to achieve red swoops and swirls in the cream. Decorate with fresh raspberries and reserved ground pistachios. Slice and serve immediately! If you have leftovers, the cake can be wrapped and stored in the fridge for up to 5 days.