Pour the caramel sauce into the prepared pan. Place pineapple halves in the sauce, pushing them to the very bottom and place cherry halves in between every two pineapple pieces, also pushing them to the bottom. Set aside.
Add the egg whites to the clean bowl and beat on medium-high speed until soft peaks are reached. Fold half of the egg whites into the batter until no white streaks or clumps remain. Then repeat with the remaining egg whites.
Remove from the oven and place it on a wire rack (without a baking sheet) to cool 10 minutes.
Place a serving plate on top of the warm cake and invert without lifting off mold or pan. Allow the cake pan to remain on top for 30 seconds. Then, remove the pan/mold. Allow the cake to cool to room temperature prior to serving.
For Baking in Advance: You may freeze the cake at this point without covering it. Then place toothpicks in the top, in about 6 places, and cover with a double layer of plastic wrap. Place in the freezer until ready to serve. Then, thaw at room temperature at least 2 hours prior to serving.
*When you use 8 slices of pineapple, there is so much pineapple juice that it creates a pineapple-caramel sauce that covers the entire cake. However, because there is so much juice, it makes the center edges of the cake quite soft, almost like uncooked batter but not quite. If you prefer a thicker caramel and less wet center edge, only use 4 full slices of pineapple.
**You have the choice of using tapioca flour or cornstarch in the flour blend recipe. I used cornstarch for mine.
***Silicone molds do not brown and harden the sides of cakes as metal pans do. However, metal retains heat, creating a higher risen, lighter cake.
***You want to prevent sugar from sticking to the sides of the saucepan. Heat until it reaches 200ºF. (If you overheat it, the butter will separate from the sugar. If this occurs, immediately cool down the mixture. Add 1/2 tablespoon of cold butter and place the saucepan on top of a frozen item from your freezer while constantly stirring until smooth and the butter incorporates into the sugar.
https://glutenfreerecipebox.com/gluten-free-pineapple-upside-down-bundt-cake-dairy-free/