Preheat oven to 350°F (175°C). Grease a 9×13-inch baking dish.
Prepare cake mix according to package directions. Replace half the water with pineapple juice. Pour into prepared pan.
Bake for 28–32 minutes until golden and a toothpick comes out clean.
In a saucepan, combine crushed pineapple and sugar. Bring to a boil, then simmer for 5 minutes.
Let the cake cool for 10 minutes. Poke holes throughout and pour syrup evenly over cake.
Cool completely at room temperature for 2 hours.
Beat cream cheese and butter until fluffy. Gradually add powdered sugar and vanilla until smooth.
Spread frosting over cooled cake. Top with toasted pecans. Chill for 1 hour before serving.
