In a large bowl, mix together pudding mix and yellow cake mix.
Make a well in the middle of the mixture, add beaten eggs, and 1 cup of reserved pineapple juice. Beat well.
Add Crisco oil and beat well. Then add vanilla and beat well.
In a small saucepan, heat the pineapple, sugar and butter together, stirring occasionally on a medium low heat. Turn temperature down and keep it on low setting.
Grease and flour a bundt pan and add cake mixture to pan and bake at 350 degrees until done. This is approximately 45 minutes depending on your oven. Check for doneness by inserting a knife or toothpick in the center.
Allow the cake to cool and poke the cake at the top every 1/2 inch with a long fork. Spoon the pineapple mixture on the cake. Place the cake in the refrigerator to chill.