What You'll Need
3-1/2 cups + 2 tablespoons (580 g) White Sonora All Purpose Flour
1-1/2 tablespoons baking powder
1 teaspoon fine sea salt
3/4 cup (180 ml) melted coconut oil or vegetable oil
2-1/2 cups (500 g) granulated sugar
3 egg yolks
1 tablespoon vanilla extract
1-1/2 cups (350 ml) whole milk
1/2 cup (60 g) raw pistachio kernels, coarsely ground
12 oz (335 g) rhubarb (fresh or frozen), chopped
3 egg whites
3/4 cup (150 g) granulated sugar
1 cup (225 g) unsalted butter, at room temperature, cubed
Preheat oven to 350 F. Grease two 9-inch round cake pans with vegetable oil and line the base with parchment paper.
In a medium bowl, whisk together the flour, baking powder and salt. Set aside.
In the bowl of a stand mixer fitted with the paddle attachment, beat the oil and sugar until combined. Add the eggs one at a time, making sure each egg is fully incorporated before adding the next. Add the yolks in the same way, then beat in the vanilla. Gradually add the dry ingredients and the milk in alternating batches and mix to combine. Use a rubber spatula to scrape the side and bottom of the bowl to make sure all the dry ingredients are incorporated, then briefly mix again.
Divide the batter evenly between the prepared cake pans and smooth the surface. Place them on the middle shelf of the oven and bake for 35 minutes, or until golden brown and a skewer inserted in the center comes out clean. Remove and cool in the pans for 10 minutes, then invert the cakes onto wire racks and allow to cool completely.
To make the buttercream, warm the rhubarb in a small saucepan over a low heat for about 15 minutes until it starts to collapse and soften. Stir and mash the rhubarb into a smooth puree, then set aside to cool completely.
Place the egg whites and sugar in the clean bowl of your stand mixer. Bring 2 cups (480 ml) water to a boil in the small saucepan and place the bowl n top, making sure the base does not touch the water. Gently heat the egg whites and sugar, whisking occasionally, until the sugar has dissolved and the temperature reaches 160 F. Transfer the bowl to the stand mixer fitted with the whisk attachment and whisk on high speed for 5 minutes, or until stiff, glossy peaks form. Add the butter one cube at a time while whisking on medium speed. When all the butter has been incorporated, add the cooled rhubarb puree and mix on low speed until it's just combined. If the mixture appears curdled after adding the rhubarb, continue to mix for a few more minutes until smooth. Store in the fridge if you're not using the buttercream immediately.
Check your cakes - if they are domed, shave off the top of the bottom cake layer with a serrated knife to flatten the surface. Spread one-third of the buttercream over the bottom layer and sprinkle with half the pistachios. Place the second cake layer on top and spread the remaining buttercream evenly over the top and side.
Sprinkle the remaining pistachios and serve.
This recipe has been reprinted with permission from The Miller's Daughter by Emma Zimmerman (Hardie Grant North America). Photo credit: David Alvarado