In a large bowl, add in the crushed pineapple with the juice and cake mix. Beat with a hand mixer on medium for about 1 minute until combined.
Pour the batter into an ungreased 10-inch angel food tube pan.
Place in the preheated oven and bake for about 40 minutes, until the top is golden brown.
As soon as the cake comes out of the oven, immediately turn the cake upside down and allow it to cool for about 2 hours.
To remove the cake from the pan, slide a knife down the outside of the cake and remove the outside of the pan. Next, slide a knife around the middle section of the cake to release it from the pan.
Topping
Add the sugar and cornstarch to a medium saucepan. Stir until the cornstarch is evenly distributed.
Add in the can of crushed pineapple and its juice and stir to combine.
Place it over medium heat and let simmer for 3 to 5 minutes until the sauce has thickened. Allow the sauce to chill for at least 1 hour.
Just before serving, slice up the angel food cake and top with the sauce.