Spray either a 13X9-inch or slightly smaller baking pan with cooking spray with flour. Heat oven to 350 degrees.
Mix cake batter according to package directions, except reduce water by 1/4 cup and add 1 can undrained crushed pineapple and 1/2 teaspoon coconut extract. Save the second can of pineapple.
Pour batter into prepared pan and bake 26-29 minutes for 13x9-inch pan and 30 -35 minutes for 11X7-inch pan.
Let cool completely. Poke holes all along top of cake.
Stir together cream of coconut and sweetened condensed milk. Slowly pour on top of cake.
Spread second can of pineapple on top of cake.
Cover and refrigerate for 2-3 hours.
Spread Cool Whip on top. If using rum extract, gently fold it into the Cool Whip first.
Sprinkle with shredded coconut.
Top with cherries.
Notes
Cake mixes used to be about 18.25 ounces but now most of them are around 16 ounces. I used to make a cake such as this one in a 13X9-inch pan, but since the new cake mixes bake up thinner, I often use a smaller pan to get a thick cake. The pan in the pictures is slightly larger than 11x7-inches.