Preheat oven to 350 degrees F. Grease and flour a bunt cake pan or tube cake pan.
Set aside 3/4 cup of crushed pineapple for the glaze.
In a large mixing bowl combine the cake mix, pudding mix, eggs, oil, and remaining pineapple. Mix on medium speed for 3 minutes. Pour the cake batter into the prepared pan.
Bake for 45 to 55 minutes or until a toothpick inserted halfway between the tube and the wall of the pan comes out clean. Remove from the oven and cool completely.
In a small saucepan melt the butter over medium heat. Add the reserved 3/4 cup of crushed pineapple, all of the reserved pineapple juice, and powdered sugar. Stir until the sugar is dissolved. Remove from heat.
Remove the cooled cake from the pan and transfer it to a serving plate. Spoon the pineapple glaze all over the cake, letting it soak in. Cut into slices and serve.