The ingredients and the simplicity of the recipe totally brought me back to being a kid, especially when I smelled that pudding mix for the first time in ages. Such a wonderful, heavenly scent. It was definitely one of those scent/memory moments for me. I will say that making this cake was a bit surreal, not only because of the pistachio flashbacks, but because it required a boxed mix. I really, really, really, don't like boxed mixes. Don't get me wrong. They're yummy and all, but there are just too many ingredients in those things for my taste. I did manage to find a relatively harmless cake mix though, that was also gluten free: Betty Crocker's Gluten-free Cake Mix. The ingredient list on the box is short and recognizable and it was really good! You wouldn't even have known that it was gluten free! So moist and yummy!
pkg. white or yellow cake mix (I used Betty Crocker's Gluten-free Cake Mix)
Combine all ingredients in large mixer bowl, then beat at medium speed for 2 minutes. Pour into greased and floured 9 x 13 inch pan. Bake for 30-35 minutes at 350 degrees. Cool and frost.
Swiss Meringue Buttercream Frosting (adapted from The Sweeter Side of Amy's Bread)
In a mixing bowl, using an electric mixer with a paddle attachment, cream the butter and shortening together for 1 to 2 minutes, until they are light in color and texture but not too soft. Scrape this mixture into a different bowl and set it aside to use later. Clean the mixing bowl to use for the egg whites.
Combine the sugar, egg whites, corn syrup, and salt in the top pan of a double boiler. Heat over simmering water, stirring frequently, until the sugar granules have dissolved and the temperature on a food thermometer registers 140ºF. Transfer the whites to the clean mixing bowl. Using an electric mixer with a whip attachment, whip the whites on medium to medium-high speed until the mixing bowl feels just cool to the touch, 10 to 12 minutes. The mixture should be white and fluffy and very thick.
Add the butter mixture and the vanilla to the egg white mixture and whip again, on medium speed, until the frosting has a smooth, creamy, spreadable texture, almost like stiff whipped cream, 1 to 2 minutes.
The frosting can be used immediately or stored in an airtight container at room temperature, but it should be used within 3 days. You may have to stir it briskly to re-fluff it if it’s been sitting for a long time.