Preheat oven to 350 degrees Fahrenheit and line cookie sheets with nonstick baking mats or lightly spray them with nonstick cooking spray.

In the bowl of an electric mixer, cream together butter, shortening, vanilla, sugar, and eggs. Add hot soda water and crushed pineapple and mix until incorporated. In a separate bowl, stir together flour, salt, and baking powder.

Add flour mixture to wet mixture and mix, scraping down the sides with a spatula to ensure it's all incorporated.

Drop by heaping spoonfuls onto prepared cookie sheets. The cookies will spread out, so I recommend having just two in each row to leave enough space. Bake for approximately 11 to 12 minutes, or just until the centers are set. You can kind of test by touching your finger in the center and it should start to spring back. Don't overbake! Once cool, store in an air-tight container and they'll get really moist!

For the frosting, add the milk to the bowl of an electric mixer, sprinkle dry pudding mix over, then add crushed pineapple and mix well. Fold in whipped topping and refrigerate until ready to serve cookies.

Frost cookies right before serving for the yummiest possible experience.