Pineapple cake, pineapple curd, and pineapple buttercream
Preheat your oven to 325 degrees F. Spray three 8-inch pans (or four 6-inch pans) with nonstick spray, line the bottoms with parchment paper, and spray again. Set aside.
In a medium sized mixing bowl, whisk together the flour, baking powder, and salt. Set aside.
In the bowl of an electric mixer, fitted with the paddle attachment, beat the butter and sugar on medium-high speed for about 3 to 5 minutes. You want the mixture to get light in color and fluffy texture. Make sure to scrape the sides and bottom of the bowl to ensure all of the mixture has combined well.
With the mixer on medium speed, add the egg whites in three additions, making sure to scrape down the sides and bottom of the bowl between each addition. Once all of the egg whites are added, turn the mixer to medium-high and beat for about 2 to 3 minutes.
Combine the powdered Dole Whip mix and buttermilk. Stir to combine. With the mixer on low speed, alternately add the flour mixture and the buttermilk mixture, starting and ending with the flour mixture. Mix only until combined.
Fold in the sour cream.
Divide the batter between the three 8-inch pans, about 22 to 24 ounces of batter in each of the 8-inch pans. Bake on the middle rack for about 30 to 35 minutes, or until a toothpick inserted in the center of the cake comes out with a few moist crumbs on it.
Let the cakes cool on write racks, in the pans, for about 15 minutes and then invert onto wire racks to cool completely. TIP: spray your write racks with nonstick spray.
NOTE: Make the curd a day before assembly
Whisk the sugar, pineapple juice, and cornstarch in a medium saucepan.
In a small bowl, whisk the whole eggs with the egg yolks and then whisk them into the pineapple juice mixture.
Turn the heat to medium-low and cook the mixture, whisking constantly, until it thickents to a pudding-like consistency. This will take 5 to 8 minutes. Once the mixture can coat a spoon, remove from heat and stir in the butter.
Strain the mixture through a fine-mesh sieve iinto a small bowl. Press plastic wrap directly onto the surface of the curd to preven a skin from forming. Refrigerate until set.
Combine the pineapple juice and Dole Whip mix. Stir to combine. Set aside.
In the bowl of an electric mixer, fitted with the paddle attachment, beat the butter for about 2 minutes, until light and fluffy and pale in color.
With the mixer on slow, gradually add the powdered sugar, then slowly add the pineapple juice. Followed by the heavy whipping cream.
Once all of the ingredients are combined, turn the mixer to medium-high and beat for about 3 to 5 minutes. Scrape down the sides of the bowl and beat for a couple minutes more. Add the food gel, if desired, and beat to combine.
Before using the buttercream, make sure to beat it by hand with a wooden spoon or large spatula to help push out the air pockets.
With your cakes at room temperature, cut each cake layer in half horizontally to create 6 layers.
Spread a small dollop of buttercream on your cake board. This will act like glue to hold your cake in place.
Place your first cake layer, top side up, on your cake board. Spread 1/4 cup buttercream across the cake. Pipe a rim of buttercream around the edge of the cake.
Spread about 1/4 cup of the curd over the buttercream.
Place the next cake layer on top of the filling and repeat these steps until you get to the final layer.
Set your final cake layer, top side down. Apply a thin layer of buttercream over your entire cake. This does not need to look pretty or be even. This coat of buttercream is simply to lock in the crumbs. Freeze your cake for about 10 to 15 minutes to set the crumb coat.
After the crumb coat is set, finish frosting your cake with the buttercream
Remember, if you want extra buttercream for thicker sides or piping, make an addition 1/4 to half batch.