Preheat oven to 350 degrees.
Pour angel food cake mix into a large mixing bowl.
Pour crushed pineapples in juice over the cake mix.
Using an electric mixer, beat on low for 30 seconds. Beat on medium speed for 1 minute.
Use a long spatula or spoon to scrape bottom of bowl and around sides to make sure both ingredients are well combined.
Pour into an ungreased 10-inch angel food pan or tube pan.
Bake 40 to 45 minutes or until deep golden brown.
HOW TO TEST TO SEE IF IT'S DONE: A thoroughly baked angel food cake has fully risen in the pan, has a dark golden-brown top covered with cracks that feel very dry, not sticky. This is the perfect time to test to see if it's done. Gently press top of baked cake with your fingertips. If it springs back, the cake is fully baked. If your fingers leave an indentation, bake 10 minutes longer. Watch carefully to prevent overbaking and burning.
Cool completely upside down for 2 hours (as directed on side of cake mix box).
Gently push a rubber spatula around edges or use hand to gently pull cake away from sides of pan.
Turn cooled cake out onto serving plate. Slice with a sharp, serrated knife.
STORAGE TIP: Wrap cake in Saran wrap. Store in refrigerator.