Preheat the oven to a temperature of 350° Fahrenheit. Meanwhile, prepare a 9x13 baking dish by applying a coat of non-stick cooking spray.

In a large mixing bowl or the vessel of a stand mixer, amalgamate the yellow cake mix, instant pistachio pudding mix, oil, eggs, and the undrained crushed pineapple. Utilize a handheld mixer and blend on medium-high speed for approximately two minutes until the mixture reaches a uniform consistency.

Transfer the prepared batter into the previously greased baking dish, ensuring it is distributed evenly.

Place the baking dish in the preheated oven and allow the cake to bake for 35 to 40 minutes. To ascertain the cake's doneness, insert a toothpick into its center; the cake is adequately baked when the toothpick emerges devoid of wet batter.

Upon removal from the oven, place the cake on a cooling rack, allowing it to reach room temperature.

Prior to commencing the frosting procedure, ensure that the cake has completely cooled.

In a mixing bowl, combine the half-and-half milk, heavy cream, and instant pistachio pudding mix. Using a whisk, mix the components for 1 to 2 minutes until well-combined. Allow the mixture to sit for approximately 5 minutes, granting it time to thicken.

Following the thickening period, incorporate the thawed Cool Whip into the mixture, ensuring even blending.

With the frosting prepared, apply an even layer atop the cooled cake.

For optimal flavor development, it is recommended to cover the cake and place it in a refrigerator for a duration of 4 to 6 hours, or alternatively, overnight. However, this step is not mandatory.