I also use 2 square pans, you can cut rectangle or square servings which more closely replicate an actual Twinkie. (There's something just wrong with a Twinkie bundt cake or round layer cake cut into wedges) Also, there's absolutely no reason that you can't use a sugar-free yellow cake and substitute regular white Splenda (not baking blend, which is concentrated) for actual granulated sugar. When was the last time that you (or friends on sugar-restricted diets) could have a Twinkie? The photos are actually of a sugar-free version. It's amazing how incredible that filling is without using cream or marshmallow fluff (unsweetened vanilla plant milk has 0 g sugar).
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TWINKIE Layer CAKE
For the cake:
1 box yellow cake mix (can be sugar-free)
3 large eggs, separated........................ 1/4 tsp. cream of tartar
1/2 cup (1 stick) butter, melted………. 1 tsp. vanilla.
1 cup milk (any kind ~ I like unsweetened vanilla almond or oatmilk)
For the Filling:
5 TB all purpose flour…………………...1 cup milk (any kind, as above)
1/2 cup shortening (i.e. Crisco)………..1/2 cup (4 TB) unsalted butter, room temp.
1/2 teaspoon salt…………………………1 teaspoon vanilla
1 cup granulated sugar (or 1 cup regular Splenda {not baking blend})
Powdered sugar for dusting
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Preheat oven to 350. Spray 2 9” square pans with non-stick baking spray (containing flour). Set aside.
Beat the egg whites with whisk attachment until foamy. Add the cream of tartar, and beat until soft peaks. Gently remove to another bowl and set aside.
Beat cake mix, egg yolks, butter, vanilla and milk in your electric mixer bowl, on medium, for about 2 minutes until light in color and creamy. Scrape the bowl and paddle. Remove from mixer and gently fold in the beatem egg whites BY HAND with a rubber scraper, until fully incorporated.
Divide the batter evenly between the two prepared pans. Bake for 25-30 minutes or until the center of the cake springs back when you touch it (and toothpick comes out clean). Let the cakes cool in the pan for 15 minutes, then invert on a wire rack to cool completely.
Meanwhile ~Make the frosting
In a small saucepan, combine the flour with milk, whisking until lumps removed. Turn on medium heat and continue to whisk until mixture becomes thick, like a pudding. Remove from heat and stir in vanilla. Cool completely.
In a mixing bowl, combine butter and sugar, beat until light and fluffy (about 2 minutes). Slowly add in the COOLED milk mixture (1/2 at a time), beating until combined. If it looks curdled, just keep beating until it becomes the texture of whipped cream (a couple of minutes ~ it's amazing how this looks & tastes then!)
Put 1 layer of cooled cake upside-down on a cake plate. (this is so you'll have 2 level sides of the cake together.) Top it with ALL of the cream filling. Put 2nd layer of cake on top. Press down so the filling reaches the edges (I evened it out with a butter knife). Sprinkle with powdered sugar. Cut into rectangles or squares to serve.
TIP: I didn't have a big square plate to put it on, so I used the lid of a big square Tupperware container (covered it with foil) as the "cake plate" and the bottom of the container as a cover for the cake.
If you're on a sugar-restricted diet but can tolerate some sugar, I recommend using real powdered sugar on top. Otherwise, you can sift together 3/4 cup regular white Splenda with 1/4 cup cornstarch to make sugar-free "powdered sugar". Keep any extra in a jar in your pantry.