01 -
Preheat your oven to 320°F (160°C). Line baking pans with parchment paper, lightly grease, and set aside.
02 -
Using a stand mixer with the whisk attachment or a handheld electric mixer, whisk egg whites on low-medium speed until foamy.
03 -
Add cream of tartar and continue whisking until soft peaks form.
04 -
Gradually add granulated sugar, about a teaspoon at a time, until stiff peaks form.
05 -
Gently fold in the chopped pistachios using a spatula.
06 -
Transfer meringue to a piping bag and pipe onto prepared baking pans, spacing out evenly and smoothing the tops.
07 -
Bake for 30-40 minutes until the top turns light golden brown. Turn the oven off and leave the meringue inside with the door closed for another 20 minutes.
08 -
Let the meringue cool enough to handle. Remove from parchment, trim edges if needed, and cool completely before assembly.
09 -
Bring water to a simmer in a large pot. In a stainless steel bowl, whisk together egg yolks, granulated sugar, vanilla extract, and salt until combined.
10 -
Place the bowl over simmering water, stirring constantly until the mixture reaches 155°F (68°C).
11 -
Transfer the bowl to the stand mixer with a whisk attachment and whisk at high speed for 6-8 minutes until the mixture is light and smooth.
12 -
Gradually add softened butter while whisking until the buttercream is thick and creamy.
13 -
Place one meringue layer on a cake stand and spread ¼ of the buttercream over it. Sprinkle with chopped pistachios. Repeat with remaining layers, ensuring the final layer has the smooth side up.
14 -
Frost the cake entirely with buttercream and press the remaining chopped pistachios onto the sides and top. Refrigerate for at least 2 hours before serving.