Pour the entire can of pineapple (fruit and juice) into a 4 cup mixing bowl. Add the contents of the carrot and raisin pouch, stir, and let sit for 5 minutes (or longer).
Meanwhile, set your oven rack to the vertical center and preheat the oven to 350F. Coat the inside of a 13x9 cake pan with a thin, even, layer of butter or non-stick spray. Dust the inside of the pan with flour, tap the sides to cover the entire surface, shake out any excess flour.
In a large mixing bowl add the contents dry cake batter pouch, the pineapple mixture, and the yogurt. Fold the ingredients together until they are fully combined with no pockets of dry mix. The batter will be very thick.
Spread the batter in an even layer in the cake pan and bake for 35 minutes. When baked the center should be sticky but firm to the touch. Let the cake cool completely before decorating and serving.
Notes
This cake is very moist and sticky. When serving use a sharp knife and wipe the blade clean between each cut.