Preheat your oven to 350°F. Prepare a 9x13 inch baking dish. Do not spray or grease the pan; the batter needs to grip the bare surface to rise properly.
Pour the dry angel food cake mix into a large bowl. Add the entire can of crushed pineapple (including all the juice) over the powder.
Using a hand mixer, start on low speed to incorporate, then increase to medium. Beat for one to two minutes until the batter is very foamy.
Pour the batter into the prepared bare pan and spread it evenly with a spatula. Bake for about 25 minutes, or until the top is golden-brown.
Remove from the oven and let cool completely on a wire rack at room temperature. Once cooled, spread the thawed whipped topping over the cake, slice, and serve.
Notes
Do not use fresh pineapple, as its active enzymes will break down the cake structure. Ensure you use the 'just add water' variety of cake mix for the best results.