Preheat oven to 350°F (175°C) and grease a 9x13-inch baking dish
In a large bowl, combine cake mix, eggs, oil, and crushed pineapple with juice
Mix until smooth and well blended
Pour batter into prepared baking dish
Bake for 30–35 minutes until golden and center is set
Cool cake completely before frosting
Whisk pudding mix with cold milk until thick
Gently fold whipped topping into pudding mixture
Spread frosting evenly over cooled cake
Chill at least 1 hour before serving
Notes
Do not drain the pineapple; the juice adds moistureCool cake fully before frosting to prevent meltingFold whipped topping gently to keep frosting lightChill before slicing for cleaner piecesStore covered in the refrigerator up to 4 daysBest served cold for a light, refreshing texture