Step 1: Prepare the white cake mix according to the package directions. Pour the batter into a greased 9x13-inch baking pan and bake as specified. Allow the cake to cool completely in the pan on a wire rack.
Step 2: Once cooled, use the handle of a wooden spoon or a similar blunt object (like a dowel or skewer) to poke holes evenly across the entire surface of the cake, about 1 inch apart.
Step 3: In a small saucepan, combine the crushed pineapple (including all the juice), granulated sugar, and 1/2 teaspoon of vanilla extract. Bring the mixture to a gentle boil over medium heat, stirring constantly until the sugar dissolves and the mixture slightly thickens, about 3-5 minutes.
Step 4: Carefully spoon the hot pineapple glaze evenly over the cooled, poked cake, ensuring it seeps into all the holes. Let the cake cool slightly while you prepare the frosting.
Step 5: In a large mixing bowl, beat the softened cream cheese and softened butter together with an electric mixer until the mixture is smooth and creamy.
Step 6: Gradually add the powdered sugar, one cup at a time, mixing well after each addition. Beat in the remaining 1/2 teaspoon of vanilla extract until the frosting is light and fluffy.
Step 7: Gently fold in about 3/4 cup of the crushed pecans into the prepared cream cheese frosting.
Step 8: Evenly spread the pecan-studded frosting over the cooled pineapple-glazed cake.
Step 9: Sprinkle the remaining 1/4 cup of crushed pecans over the top of the frosting. Cover the cake tightly and refrigerate for at least 6 hours, or preferably overnight, before serving for best results.