Preheat oven to 350 degrees. Spray a 12 cup Bundt pan generously with non stick cooking spray. (We like to use Bakers Joy that has flour added to the spray.)
Drain pineapple juice from the crushed pineapple. Hopefully you will get about 1 cup pineapple juice from it. Set aside.
Beat cake mix, dry pudding mix, eggs, vegetable oil, and 3/4 cup pineapple juice in a large bowl with an electric mixer for 2 minutes.
Add vanilla into the cake batter.
Fold in crushed pineapple and pour into the prepared pan.
Bake 40-42 minutes or until toothpick inserted comes out clean.
Sweet Filling
While the cake is cooking, combine remaining 1/4 cup of pineapple juice, vanilla, powdered sugar, and melted butter into a small bowl.
When the cake is done cooking, remove from the oven and set on a wire rack or dish towel to cool while in the pan.
Right after removing it from the oven, poke holes in the cake with a skewer at 1/2 inch spaces while still hot and in the pan.
Pour the sweet filling over the cake so it will go into the holes. I used a big spoon and drizzled it over all the holes. (If the sweet filling begins to pool, just poke additional holes)
Allow to cool in pan for about 40 minutes. Then invert cake onto a serving platter, and remove pan.
Cool completely.
Glaze
Beat glaze ingredients together until smooth. Drizzle over cooled cake.
Notes
Immediately after placing the cake on the wire rack, take the skewer and poke the cake about 1/2 inch apart while the cake is still hot in the pan.