Prepare 1 box yellow cake mix with (ingredients needed to make cake; eggs, oil and water) and bake according to package directions for a 9x13-inch baking pan.
While cake is baking, stir together 20 ounce can crushed pineapple in juice and 1 cup sugar in a small saucepan over medium heat.
Bring to a boil, stirring constantly, until the sugar is dissolved (about 2-3 minutes). Remove from heat and wait for cake to finish baking.
Once the cake is finished baking, while still hot, poke holes all over the top with a fork.
Pour the warm pineapple mixture over the cake. Spread out the pineapple mixture so it evenly covers the cake.
Allow the cake to cool completely. Once cake is cooled, it's time to start the frosting.
In a large bowl, beat together 8 ounce block cream cheese, softened to room temperature and 11/2 cup salted butter (1 stick), softened to room temperature using an electric or stand mixer) on medium speed until smooth, about 2 minutes.
Gradually add in 3 cups powdered sugar (a little at a time) beating until the frosting is smooth and creamy. Remember, if using a stand mixer, to occasionally scrape down the sides.
Finally, stir in 1/2 cup chopped pecans.
Drop the frosting by dollops onto the cake. Smooth and spread it to coat.
Cover and refrigerate the cake until fully chilled before serving (2 hours). This gives time for the flavors to come together so don't skip this step.
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Notes
The cake will keep for up to 5 days when stored, covered, in the fridge.