Step 1

Heat oven to 350°. Spray a 9x13 baking pan with cooking spray.

Step 2

In a large mixing bowl, or the bowl of a stand mixer, combine cake mix, instant pudding mix, oil, eggs, and crushed pineapple (do not drain!). Beat with a handheld mixer on medium-high speed for 2 minutes, or until combined well.

Step 3

Pour batter into prepared baking dish and spread out evenly.

Step 4

Bake for 35-40 minutes or until a toothpick inserted into the middle of the cake comes out clean.

Step 5

Let cool completely on a cooling rack.

Step 6

Do not frost the cake until the cake is completely cooled.

Step 7

Add both milks and instant pistachio pudding into a mixing bowl. Whisk together for 1-2 minutes until it's mixed well. Let sit for 5 minutes to thicken up.

Step 8

Stir in the Cool Whip until everything is mixed well. Frost the cake.

Step 9

Cover the pan with tin foil or a lid and let refrigerate for 4-6 hours, or overnight for best results, before serving. * It's not completely necessary to refrigerate the cake before serving but I find that it tastes best that way. The frosting gets really thick and the cake soaks in all the flavors.